The Old Testament was written by non-Christians for non-Christians

Actually, there not being any Christians in the Old Testament doesn't prove the Old Testament doesn't lead to Christ for the following reasons. (1) Coming to Christ does not make one a Christian. So the Old Testament believers among the Jewish people who did come to Christ were lead to him by their Scriptures, but this did not make them Christians. Not being a Christian simply means you don't live by the Christian law as set out in New Testament times after Christ came, but before he came a person could still have a relationship with Christ. (2) Even if the Old Testament didn't lead the Jews as a nation to Christ during the Old Testament period, this does not show these same OT writings could not lead people to Christ at a later time, such as when Jesus Christ walked the earth. Now here are a few facts which show the Old Testament writings did indeed lead people to Christ: (1) First century Jews and other believers who came to Christ, credited the Old Testament Scriptures, and Jesus himself built his doctrine from Old Testament prophecy and law. The New Testament was not yet written when Jesus walked the earth, so the primary Bible of the early Christian Church (which was very Jewish in its beginning - Jesus was a Jew) was the Old Testament. For examples: (a) Salvation through Jesus was a central part of early Christianity, yet Paul says to Timothy: "and how from infancy you have known the Holy Scriptures, which are able to make you wise for salvation through faith in Christ Jesus." (2 Tim 3:15 NIV) Here Paul is saying the Old Testament pointed Timothy to Christ. (b) "Therefore the Law has become our tutor to lead us to Christ, so that we may be justified by faith." (Gal 3:24 NASB) The Old Testament law of Moses is said to lead to Christ. (c) Jesus himself said that he came to fulfill the Old Testament law. "Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them." (Matt 5:17 NIV) (d) "[Jesus] said to them, "This is what I told you while I was still with you: Everything must be fulfilled that is written about me in the Law of Moses, the Prophets and the Psalms." Then he opened their minds so they could understand the Scriptures. He told them, "This is what is written: The Messiah will suffer and rise from the dead on the third day, and repentance for the forgiveness of sins will be preached in his name to all nations, beginning at Jerusalem." (Luke 24:44-47) The OT did point them to Christ, since Jesus himself used the OT to validate his identity and mission, and they believed him. The writers of the NT quoted the Hebrew Scripture OT hundreds of times. According to a listing published by Westcott and Hort, the combined total of quotations and references is some 890. (The New Testament in the Original Greek, Graz, 1974, Vol. I, pp. 581-595) Examples are drawn from the Hebrew Scriptures by all the inspired Christian writers. (1Co 10:11) These later writers acknowledge and include the Hebrew Scriptures as inspired of God and beneficial for completely equipping the man of God for every good work."2Ti 3:16,"17; 2Pe 1:20,"21. From the days of the faithful man Abel, God"s servants had eagerly looked forward to the Seed foretold by God himself. (Genesis 3:15; 4:1-8; Hebrews 11:4) It had been revealed that the Seed would serve God"s purpose as the Messiah, meaning "Anointed One." He would "finish off sin," and the glories of his Kingdom were foretold in the psalms. (Daniel 9:24-26; Psalm 72:1-20) Jesus was recognized as the Messiah on the basis of him fulfilling many OT prophecies. Andrew rushed to his brother Simon Peter and told him: "We have found the Messiah." (John 1:41) Jesus" disciples were convinced that he was the promised Messiah. (Matthew 16:16) Jesus" lineage lays the first basis for identifying him as the promised Messiah. Jehovah had told His servant Abraham that the promised Seed would come from his family. Abraham"s son Isaac, Isaac"s son Jacob, and Jacob"s son Judah each received a similar promise. (Genesis 22:18; 26:2-5; 28:12-15; 49:10) The line of the Messiah"s descent was narrowed down centuries later when King David was told that his family line would produce this One. (Psalm 132:11; Isaiah 11:1,"10) The Gospel accounts of Matthew and Luke confirm that Jesus came through that family line. (Matthew 1:1-16; Luke 3:23-38) Though Jesus had many bitter enemies, none of them challenged his well-publicized line of descent. (Matthew 21:9,"15) Clearly, then, his lineage is beyond question. However, the Jews" family records were destroyed when"the Romans sacked Jerusalem in 70"C.E. In later times, no one could ever prove a claim to be the promised Messiah. Fulfilled prophecy is a second line of evidence. Scores of Hebrew Scripture prophecies describe various aspects of the Messiah"s life course. In the eighth century"B.C.E., the prophet Micah foretold that this great ruler would be born in the insignificant town of Bethlehem. Two towns in Israel were named Bethlehem, but this prophecy specified which one: Bethlehem Ephrathah, where King David had been born. (Micah 5:2) Jesus" parents, Joseph and Mary, lived in Nazareth, some 90 miles [150"km] north of Bethlehem. While Mary was pregnant, however, the Roman ruler Caesar Augustus ordered all the people to register in their home cities. So Joseph had to take his pregnant wife to Bethlehem, where Jesus was born."Luke 2:1-7. So many people were led to Jesus because of the OT writings during the time of Christ. (2) Jesus is he God of the OT, therefore, by coming to Yahweh/Jehovah, the OT Jews were coming to Jesus. (a) Isaiah 9:6 said from the beginning that it was God himself "mighty God" who would be born as a child. So the Messiah is God. (b) Isaiah 40:3 speaks about preparing the way for the LORD (Yahweh). When we compare this verse with Mark 1:3 we see that Jesus is the LORD who had the way prepared for him by John the Baptist. In Joel 2:32a it says that whoever calls upon the Name of the LORD (Yahweh) will be saved. This verse is quoted by Peter in Acts 2:21, and by Paul in Romans 10:13. Both apostles are clearly referring to Jesus as the LORD. In Isaiah 6:1-10 we read about the marvelous vision that Isaiah had revealing the glory of the LORD (Yahweh). John tells us in John 12:40-41 that this vision revealed the glory of Jesus. In Isaiah 44:6, the LORD (Yahweh) refers to himself as "the First and the Last". In Revelation 1:8 and 17, Jesus similarly refers to himself as "the Alpha and the Omega" and "the First and the Last". In Genesis 1:26 God speaks of himself in the plural, "Let US make man in OUR image." No monotheistic Jew would believe that they were created by angels, so to whom was God speaking? Isaiah 44:24 tells us that Yahweh made all things, streached out the heavens alone, spread out the earth by himself; yet Scripture reveals the Father as creator (Isa 64:8), and the Son (Col 1:16-17; Heb 1:2, 8-10), and the Holy Spirit (Ps 104:30; Job 26:13; 33:4) Yet, the first Christians were monotheistic Jews whose beliefs were based on completely monotheistic OT Scriptures even before they wrote the NT. Deu 4:35; Isa 43:10-11; 44:6, 8; 45:5-6, 14, 21-22; 46:9; Mal 2:10; Rom 3:30; 1 Cor 8:6; Eph 4:6; Jam 2:19) So it makes sense that Jesus is the God of the OT, which agrees with the fact that Micah 5:2 says the Messiah EXISTED BEFORE HE WAS BORN AS A HUMAN. So by coming to Yahweh, OT Jews were coming to Jesus, and when he came as a man, he made God's triune nature more clear. But even in the OT God appears as a man. (Gen 18) I think that rebuts your argument.