Rev 6:3

“"And when He had opened the second seal, I heard the second living creature saying, Come and see. And there went out another horse that was red, and to him that sate upon him was given a great sword." The red horse, and he that sate upon him, having a sword, signify the coming wars, as we read in the Gospel: "For nation shall rise against nation, and kingdom against kingdom; and there shall be great earthquakes in divers places." This is the ruddy horse.”

“The same words of exhortation to "come and see" are repeated, but for a different reason. The white horse is portrayed as good, but the red horse is portrayed as evil. Just as in regard to the good, joy is promised for the church's victory, so here there is a warning against evil from a foreknowledge of the future.”

“I suppose that the second living creature is the bull to depict the sacred sacrifices of the holy martyrs, since the first [creature] signified the apostolic authority.”

“And when he had opened the second seal, I heard the second living creature, saying: Come, and see. What does it mean that a similar command is given in a dissimilar situation, if not that concern for the future struggle is here given in the same way as joy for the achieved victory was above?”

“But secondly, there is the blessing of Christ to us, who opened the second seal of the little scroll, and added to us the release of our shame, restoring to us the divine vision; He was tempted as the Lord and overcame the tempter so that He might show not only victory but also that the adversary was defeated. The adversary did not bite the heel of the rider nor trip up our steps (Ps. 140:4) according to God's commandments, but rather, falling backward and being sent away in servitude, and hearing from the Man whom he wrestled with long ago, even though God was in Him, He said, "Depart, Satan," (Matt. 4:10) and Satan went away in shame. And now, for the first time, the adversary knowing his own weakness, he who boasts of sitting above the clouds on his throne, will be made like the Most High, imagining himself according to what was described by Isaiah. (Isa. 14:13-14) When it happened, a fiery red horse came out, led by one of the holy creatures; and to the one sitting on the horse it was given the power to take peace from the earth so that people would kill one another, and a great sword was given to him. The fiery red horse is a riddle [αἴνιγμα] of blood; therefore, a sword is given to the one seated upon it, by which to destroy and divide the unity of those on earth toward evil. They were united in their idolatry and so that they might kill one another; that is, to destroy each other through hostile contracts. For the Lord "did not come to bring peace upon the earth, but a sword; and to set a son against his father, and a daughter-in-law against her mother-in-law," (Matt. 10:34-35) the new and godly against the ancient and condemned.”