1-Abraham (Genesis 12)
The first pre-incarnate appearance of the Son of God in the Old Testament was in Genesis 18. We read how He, in a human form, along with two of His angels, visited Abraham. “Then the Lord appeared to him by the terebinth trees of Mamre, as he was sitting in the tent door in the heat of the day” (Genesis 18:1). And in Genesis 18:13, we read that He was called “the LORD.” Whenever the word LORD appears in scripture with all caps, this points to God’s name Jehovah or Yahweh.
And in Genesis 22:11,12, when God tested Abraham to offer his son Isaac to give him a glimpse of the Almighty’s sacrifice to redeem mankind (Genesis 3:15), we read that the angel of the Lord was identified as God. “But the Angel of the Lord called to him from heaven and said, “Abraham, Abraham!”… And He said, “Do not lay your hand on the lad, or do anything to him; for now I know that you fear God, since you have not withheld your son, your only son, from Me.”
It’s noteworthy to mention that Abraham also encountered Melchizedek the High Priest and King of Salem (Genesis 14:18-20), who some teach that he represented Christ. The Bible tells us that Melchizedek was one of the contemporaries of Abraham, king of one of the small areas of that time (see Who was Melchizedek?).
The second appearance of the Son of God can be found in Genesis 32:24-30 where we read how Jacob wrestled with a being. This Being was Christ in human form. Jacob would not let go of the heavenly Being until he received a blessing. So, the Lord granted him his request. And his name was changed to Israel which means “he who prevails with God” or “he will rule as God (rules).”
Jacob realized whom he wrestled with in Genesis 32:30. So, he memorialized the spot of his personal experience with God by a name meaning the “face of God.” The fact that he had seen God face to face and yet lived was a true miracle (Exodus 33:20; Judges 6:22; 13:22; Isaiah 6:5).
In Judges 6:11-24, the soon-to-be judge, Gideon was greeted by the Angel of the Lord, who sat down under an oak tree. Gideon asked why the Lord had not fulfilled the wonders He promised the people of Israel that he was waiting for. The phrase “the LORD turned to him” identified the Angel as the Lord Himself.
Gideon later brought food which the Angel of the Lord’s staff consumed with fire. Then, He swiftly disappeared. Gideon’s reply to such a sight in verse 22 was, “Ah, Sovereign LORD! I have seen the angel of the LORD face to face!” He feared dying from seeing the living God. The Lord replied in verse 23, “Peace! Do not be afraid. You are not going to die.” Clearly, this angelic like Being was Christ the Lord.
Another example where Christ appeared in the Old Testament can be found in Genesis 16:7-13. Hagar called the Angel of the Lord “LORD,” “God,” and “One.” We read, “Then she called the name of the Lord who spoke to her, You-Are-the-God-Who-Sees” (Genesis 16:13).
Believing that anyone that sees God would die (Exodus 20:19; 33:20), Hagar was surprised to have seen Him and yet remained alive. So, she called Him “God of seeing,” for He not only had seen her and spoken to her in her trouble but had also allowed her to see Him and live.
In Exodus 3:2-6, the Angel of the LORD declared Himself to be God. “And the Angel of the Lord appeared to him (Moses) in a flame of fire from the midst of a bush. So he looked, and behold, the bush was burning with fire, but the bush was not consumed…God called to him from the midst of the bush …Then He said, “Do not draw near this place. Take your sandals off your feet, for the place where you stand is holy ground.”
Moreover He said, “I am the God of your father—the God of Abraham, the God of Isaac, and the God of Jacob.” And Moses hid his face, for he was afraid to look upon God.”
The context of verses 4–6 and 14 makes it clear that this “angel of the Lord” was Christ. Already in Abraham’s time, the Lord had shown Himself with this name (Genesis 22:11). In addition, the place where Moses stood was holy, not because it was a sacred spot but because of the presence of God.
Christ claimed the same title “I am” for Himself when He said, “Most assuredly, I say to you, before Abraham was, I AM” (John 8:58). Christ by saying He was the “I Am,” claimed to be God. The Jews understood this phrase as a claim to divinity. So, “they took up stones to throw at Him” in order to stone Him for blasphemy (John 8:59).
In Joshua 5:13-15, we read how Christ appeared to Joshua. God’s servant was near Jericho when he saw a man with a sword drawn. Immediately Joshua wanted to know if he was a friend or a foe. And he was told by the man that he was captain of the Lord’s host.
Upon hearing this, Joshua fell on his face and worshiped him. And this man did not stop Joshua from worshiping Him as any other servant of the Lord would do (Acts 10:26; 14:15; Revelation 19:10; 22:9).
Joshua asked Christ what His message was and the Lord responded by telling him to take off his shoes because he was standing on holy ground, which is the same command He told Moses, when He appeared to him in a burning bush (Exodus 3:5).
Another example of Christ in the Old Testament was given by Hosea who also referred to the Lord both as God and as an Angel. “He took his brother by the heel in the womb, and in his strength he struggled with God. Yes, he struggled with the Angel and prevailed; he wept, and sought favor from Him. He found Him in Bethel, and there He spoke to us” (Hosea 12:3, 4). In this passage, God confirmed His covenant and the promise to Israel for He had the power and the authority to do so (Psalm 103:19).
8-Shadrach, Meshach and Abednego
The last example of where Christ appeared in the Old Testament was with Shadrach, Meshach and Abednego in the fiery furnace. King Nebuchadnezzar cast these 3 men into a fiery furnace for refusing to worship an idol he made.
But after casting them into the furnace, the king noticed a fourth man. Then the king said, “I see four men loose, walking in the midst of the fire; and they are not hurt, and the form of the fourth is like the Son of God” (Daniel 3:25). Christ came down and saved these men from perishing in the fiery furnace.
Upon seeing this miracle King Nebuchadnezzar repented and proclaimed, “Blessed be the God of Shadrach, Meshach, and Abed-nego, who hath sent his angel, and delivered his servants that trusted in him, and have changed the king’s word, and yielded their bodies, that they might not serve nor worship any god, except their own God” (Daniel 3:28).
The above were some references where Christ appeared in the Old Testament to bless, guide and comfort His children. And after the ministry of the Son of man on earth, He appeared several times in the New Testament as well. https://bibleask.org/what-were-the-post-resurrection-appearances-of-jesus-christ/
In His service,