There is no contradiction; there is a very important distinction involved. Jesus taught a crucially important distinction to all those disciples gathered, Thomas in particular, in asking, "“Have you believed because you have seen me? Blessed are those who have not seen and yet believe.”
Thomas’ answer would have been, if he had needed to answer, “No, my Lord - now I “see” and understand. I believe in you
not because I saw you and/or touched you and your wounds. I believe because I was changed in my soul. In my soul was revealed to me what was revealed to Peter before the Passion ever came. Flesh and blood did not reveal this to me, but the Father in heaven!”
Jesus confirmed this inner work of God in Thomas’ soul, when He said “Blessed are those who have
not seen and yet believe.”
Thomas became one of those “blessed” as Jesus stood in front of Him, offering to Thomas an opportunity to confirm in Thomas’ “flesh” that Jesus, resurrected, was alive and right there in front of him. But Thomas no longer needed or wanted a confirmation by “flesh and blood” - he received in interior confirmation directly from God in his soul! Thus he was one of the blessed who believed not because “flesh and blood” (that is by a natural human “proof”) revealed it, but Thomas was blessed with faith to say - as Peter did before - “My Lord and my God” -
by the work of God in him.
Do you see this? To Mary Magdalene Jesus was teaching His necessary Ascension. Unless He ascended, the Holy Spirit could not be poured out to humanity. To Thomas Jesus was teaching the necessity of supernatural Faith - faith infused directly by God into the soul. This kind of faith is necessary for salvation.
There are two radically different and distinct kinds of faith:
- natural faith, such as a man gains by reasoning, by argument, by seeing miracles, by childhood upbringing, and so on - by man’s natural faculties. This kind of faith is very common, but is not in itself salvific, as Paul teaches:
[Eph 2:8 ] For by grace you have been saved through faith; and this is not your own doing, it is the gift of God—
[Eph 2:9 ] not because of works, lest any man should boast.
- supernatural faith:
Grace, the free gift of God, infuses the supernatural virtue of faith in the soul - bringing the justification that leads to salvation. The works of the natural man - works of his intellect, works of his memory and will, cannot justify him - no man can save himself. As St. Thomas Aquinas (I think) said, “Only God can reveal God.”
Many words - I hope this is clear.