To fully understand what is happening, it is useful to recognize where various events occur. The apostle John is in the
Temple of God, because the book with the seals are in God's hand (Rev 5:1), and when
Jesus takes it, the 24 elders surrounding God's throne bowed down to Him (Rev 5:8).
When the third seal is broken, a seraph calls out a black horse whose rider had a pair of scales in his hand. The black
horse rider is tasked with taking away food security with famine and food inflation.
This is not the first mention of colored horses and their riders.
In Zechariah's eighth vision (Zech 6:1-8), he sees four chariots,
which are the four spirits of heaven. These four chariots / spirits of heaven are angels
(2 Ki 6:15-17; Ps 68:17;
Isa 66:15). Going forth between standing before God and patrolling the earth, the second
chariot, being pulled by black horses, lead the white horsed chariot to the north country to do something to appease God's wrath.
Without much detail, it is difficult to understand Zechariah' prophecies; however, one can gain a better understanding of
the colored horses and their riders who emerge with the breaking of the first four seals, and they all work in concert.