The 'Old Testament Saints'? Who are they and what evidence have you that the Messiah is more than a man?
Job didn't believe that the Messiah was a mere man. I Know My Redeemer Lives
We do not “know” that Christ lives, just because this idea makes us feel good. Here is how we really know, and know that we know.
We have the testimony of the scriptures. (1) David prophesied that though Christ would be murdered, he would rise from the grave (Psalm 16:10; cf. Acts 2:25ff). (2) Isaiah foretold that while Jehovah’s suffering Servant would be put to death, nonetheless he would “see his seed” (i.e., numerous spiritual offspring, cf. Isaiah 11:1; Romans 7:4; Hebrews 2:13), and his days would be prolonged (Isaiah 53:10b). (3) Jesus himself promised he would be raised from the dead (Matthew 16:21; John 2:19, 21). (4) Many witnesses testified to the fact that Christ was raised to die no more (Romans 6:9; Revelation 1:18). For a consideration of some of those witnesses, see 1 Corinthians 15:1-8.