Note: Word studies such as this is a wonderful way to learn from scholars who have unearthed facts about linguistics and etymology and bring to light insights and perspectives that would otherwise be missed. However the study of biblical terms within the background and context of ancient worlds and cultures do pose a risk. For the uninformed, the risk is assuming that a term always has a certain technical meaning. Language is not so rigid, and one must bear in mind the context of the passage to fully appreciate the beauty and meaning of a term.

When the LXX (Greek Old Testament) was produced by Jewish translators, the Hebrew root verb 'āman was translated with the Koine Greek verb "pisteuō."

Pisteuō means "to believe" or "trust / entrust."

Pisteuō, is used in the following places of the Septuagint: Genesis 15:6; 42:20; 45:26; Exodus 4:1, 8; 14:31; 19:9; Numbers 14:11; 20:12; Deuteronomy 9:23; 28:66; 1 Samuel 3:21; 27:12; 1 Kings 10:7; 2 Kings 17:14; 2 Chronicles 9:6; 24:5; 32:15; Job 4:18; 9:16; 15:15, 31; 24:22; 29:24; 39:12; Psalms 26:13; 77:22; 105:12; 115:1; 118:66; Proverbs 14:15; 24:24; Isaiah 7:9; 28:16; 43:10; 53:1; Jeremiah 12:6; 25:8; 47:14; Lamentations 4:12; Daniel 6:23; Jonah 3:5 and Habakkuk 1:5.

In the New Testament, pisteuō is consistently in reference to "believing with a trust that saves" in God and His word revealed through instruments such as Moses (John 5:46), prophets (Luke 24:25; Acts 26:27), angels (Luke 1:20-45; Acts 27:25) and Scripture (John 2:22; Acts 24:14).

Frequently pisteuō is used in combination with a Greek preposition forming "pisteuō eis", which means "believe in." This was in contrast to the LXX or Greco-Roman thought, in which faith was understood as "believe that;" it was uncommon to understand faith as "believe in." "Believe in" brings a focus on the object of faith - Jesus Christ Himself:

Pistis is a Greek noun that essentially means "faith" or "a trustful human response to God's self revelation via His words or actions."

Pistis, is used in the following places of the Septuagint: Deuteronomy 32:20; 1 Samuel 21:2; 26:23; 2 Kings 12:15; 22:7; 1 Chronicles 9:22, 31; 2 Chronicles 31:12, 18; 34:12; Nehemiah 9:38; Psalms 32:4; Proverbs 3:3; 12:17; 14:22; 15:27; Jeremiah 5:1; 7:28; 9:3; 15:18; 35:9; 39:41; 40:6; Lamentations 3:23; Hosea 2:20 and Habakkuk 2:4.

After the resurrection of Jesus Christ, the gospel became a tradition of teaching which laid claim to be received by faith. This call for pistis, in the name of Jesus Christ, involved the renunciation of existing cult piety and rabbinical teaching.

When pistis appears with the definite article, "the faith" is in reference to Christian beliefs (i.e. Rom 4:16; 1 Cor 16:13). It is about a saving faith based on the historical event of Jesus' crucifixion and resurrection and promise of future salvation for the believing human being.

The derivative nouns of the Hebrew root verb 'āman (i.e. 'ēmūn, 'ĕmûnâ, 'ĕmet, etc) were translated with Greek terms of the "pistis" word group.

The Hebrew root verb bāṭaḥ was translated with the Greek verb "elpidzō," which means "to hope," or with the Greek term "pepoitha", which means "trust" or "rely upon".