At age 99, Abraham personally meets God for the second time (Gen 17:1, Gen 12:7 is the first recorded time). At this meeting, God makes a commitment He never stated before in prior promises to Abraham:

I will establish My covenant between Me and you and your descendants after you throughout their generations as an everlasting covenant, to be God to you and to your descendants after you. (Gen 17:7)

But what does this mean, "to be God to you?"

At this second in person meeting, God clarifies the Abrahamic Covenant and provides context to what it means "to be God to Abraham and his descendants."

In contrast to Abraham's pagan background (Josh 24:2), "being God to Abraham" is a historically real and living supernatural Being who makes a contemporary, unilateral, unconditional, and everlasting covenant (Gen 15:17-21). A formal relationship is established between God and a human being.

Who changes Abram's name to Abraham (Gen 17:5) and Sari to Sarah (Gen 17:15).

Who defines the qualifications of who He chooses to be God to (Gen 17:7).

God's chooses to be God to only those who have the faith of Abraham, which Jesus defines as a descendant of Abraham (John 8:39-44) as well as the apostle Paul (Rom 4:13-15; Gal 3:6-9). God does not determine who comes to faith; God only wants to be God to those who choose to have faith in Him. Note: the Abrahamic Covenant was made after Abraham placed his faith in God.

Who provides a place of refuge that the descendants of Abraham can possess (Gen 17:6-8).

When the Abrahamic Covenant is ratified, God defines the physical dimensions of the Promised Land (Gen 15:18), which match the physical dimensions of the eschatological New Jerusalem (Rev 21:15-16).

Who plans to the smallest detail as exemplified by clarifying who will have the covenant with God (Gen 17:18-19): the promised unborn son Isaac named by God [born of Sarah Abraham's betroth] over Abraham's firstborn Ishmael [born of Sarah's handmaiden].

At a later covenant event, just before presenting the Law to the sons of Israel, God sought a covenant agreement in the process of fulfilling His promise to Abraham to be God to his descendants. It was a conditional covenant to teach what the faith of Abraham meant and how to be holy by learning what sin was and how to atone for it.

And Moses went up to God, and the Lord called to him from the mountain, saying, "This is what you shall say to the house of Jacob and tell the sons of Israel: 'You yourselves have seen what I did to the Egyptians, and how I carried you on eagles' wings, and brought you to Myself. Now then, if you will indeed obey My voice and keep My covenant, then you shall be My own possession among all the peoples, for all the earth is Mine; and you shall be to Me a kingdom of priests and a holy nation.' These are the words that you shall speak to the sons of Israel." (Ex 19:3-6)

"To be God to Abraham and his descendants" is a choice that God makes because of one's faith. It means that when God chooses you because of your faith, He brings you to Himself and possesses you "among all the peoples." This possession occurs immediately, and in the future, when all Believers are in the presence of God, there will be eternal life in the absence of "mourning, crying, or pain."

Then I saw a new heaven and a new earth; for the first heaven and the first earth passed away, and there is no longer any sea. And I saw the holy city, new Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband. And I heard a loud voice from the throne, saying, "Behold, the tabernacle of God is among the people, and He will dwell among them, and they shall be His people, and God Himself will be among them, and He will wipe away every tear from their eyes; and there will no longer be any death; there will no longer be any mourning, or crying, or pain; the first things have passed away." (Rev 21:1-4)

"To be God to Abraham and his descendants" means that a Believer will serve God in a specific way. You are stewards of and obedient to God's word.

and you shall be to Me a kingdom of priests and a holy nation.' These are the words that you shall speak to the sons of Israel." (Ex 19:6)

Moses understood the significance of this covenant "to be God to Abraham and his descendants." Heaven and the highest heavens belong to God, yet He chose the descendants of Abraham, Isaac, and Jacob, because of His love for them. The covenant with Abraham, Isaac, and Jacob was unilateral and unconditional!

And now, Israel, what does the Lord your God require of you, but to fear the Lord your God, to walk in all His ways and love Him, and to serve the Lord your God with all your heart and with all your soul, and to keep the Lord's commandments and His statutes which I am commanding you today for your good? Behold, to the Lord your God belong heaven and the highest heavens, the earth and all that is in it. Yet the Lord set His affection on your fathers, to love the, and He chose their descendants after them, you over all the other peoples, as it is this day. (Deut 10:12-15)

When the nation of Israel failed in their covenant commitments, which reflected their lack of faith, God expelled them from the Promised Land. But as "God to Abraham and his descendants," God was committed to fulfill His covenant promises to Abraham and provided another way for his descendants to enter the Promised Land – a New Covenant.

Therefore I poured out My wrath on them for the blood which they had shed on the land, because they had defiled it with their idols. Also I scattered them among the nations and they were dispersed throughout the lands. According to their ways and their deeds I judged them. When they came to the nations where they went, they profaned My holy name, because it was said of them, 'These are the people of the Lord; yet they have come out of His land.' But I had concern for My holy name, which the house of Israel had profaned among the nations where they went.
"Therefore say to the house of Israel, 'Thus says the Lord God, "It is not for your sake, O house of Israel, that I am about to act, but for My holy name, which you have profaned among the nations where you went. I will vindicate the holiness of My great name which has been profaned among the nations, which you have profaned in their midst. Then the nations will know that I am the Lord," declares the Lord God, "when I prove Myself holy among you in their sight. For I will take you from the nations, gather you from all the lands and bring you into your own land. Then I will sprinkle clean water on you, and you will be clean; I will cleanse you from all your filthiness and from all your idols. Moreover, I will give you a new heart and put a new spirit within you; and I will remove the heart of stone from your flesh and give you a heart of flesh. I will put My Spirit within you and cause you to walk in My statutes, and you will be careful to observe My ordinances. You will live in the land that I gave to your forefathers; so you will be My people, and I will be your God. (Ezek 36:18-28)

"To be God to Abraham and his descendants" is a commitment God makes that includes solutions when there are counterparty failures that threaten the fulfillment of His covenant.

God does not associate Himself with those who misrepresent and make Him indistinguishable from pagan gods. God made the New Covenant to establish the holiness of the name YHWH, I AM WHO I AM, I AM HE WHO EXISTS!

Through His Son Jesus Christ, the New Covenant was inaugurated with Jesus whose very name means "Yahweh is salvation." God literally vindicated the holiness of His great name, and through the name of Jesus Christ, nations see God (John 5:19-23; 14:7).

Therefore Jesus answered and was saying to them, "Truly, truly, I say to you, the Son can do nothing of Himself, unless it is something He sees the Father doing; for whatever the Father does, these things the Son also does in the same way. For the Father loves the Son and shows Him all things that He Himself is doing; and the Father will show Him greater works than these, so that you will be amazed. For just as the Father raises the dead and gives them life, so the Son also gives life to whom He wishes. For not even the Father judges anyone, but He has given all judgment to the Son, so that all will honor the Son just as they honor the Father. The one who does not honor the Son does not honor the Father who sent Him. (John 5:19-23)

If you had known Me, you would have known My Father also; from now on you know Him, and have seen Him."
Philip said to Him, "Lord, show us the Father, and it is enough for us." Jesus said to him, "Have I been with you for so long a time, and yet you have not come to know Me, Philip? The one who has seen Me has seen the Father; how can you say, 'Show us the Father'? Do you not believe that I am in the Father, and the Father is in Me? The words that I say to you I do not speak on My own, but the Father, as He remains in Me, does His works. Believe Me that I am in the Father and the Father is in Me; otherwise believe because of the works themselves. (John 14:7-11)

"To be God to Abraham and his descendants" is a commitment to a real life relationship, a spiritual communion with a Believer. It is an agapē love relationship that sanctifies. It is a concept of love the world has never known before until its introduction by God’s word.

"Then I will sprinkle clean water on you, and you will be clean; I will cleanse you from all your filthiness and from all your idols. Moreover, I will give you a new heart and put a new spirit within you; and I will remove the heart of stone from your flesh and give you a heart of flesh. I will put My Spirit within you and cause you to walk in My statutes, and you will be careful to observe My ordinances. You will live in the land that I gave to your forefathers; so you will be My people, and I will be your God." (Ezek 36:25-28)

For God so loved (agapaō) the world, that He gave His only Son, so that everyone who believes in Him will not perish, but have eternal life. For God did not send the Son into the world to judge the world, but so that the world might be saved through Him. (John 3:16-17)

Jesus answered and said to him, "If anyone loves (agapaō) Me, he will follow My word; and My Father will love (agapaō) him, and We will come to him and make Our dwelling with him. The one who does not love Me does not follow My words; and the word which you hear is not Mine, but the Father's who sent Me.
These things I have spoken to you while remaining with you. But the Helper, the Holy Spirit whom the Father will send in My name, He will teach you all things, and remind you of all that I said to you." (John 14:23-26)

"To be God to Abraham and his descendants" is a commitment to include the Believer's name in the Book of Life.

Then those who feared the Lord spoke to one another, and the Lord gave attention and heard it, and a book of remembrance was written before Him for those who fear the Lord and who esteem His name. "They will be Mine," says the Lord of hosts, "on the day that I prepare My own possession, and I will spare them as a man spares his own son who serves him." So you will again distinguish between the righteous and the wicked, between one who serves God and one who does not serve Him. (Mal 3:16-18)