Jewish scripture exposes everything about the Jews: the good, bad, the embarrassing, ugly, wicked, evil, their immorality, idolatry and their captivity. Nothing is hidden and there is no credible reason or motivation as to why they would have corrupted their own heritage. It is because of the Principle of Embarrassment that Jewish scripture is credible, in the same way that a judge is likely to believe a witness who exposes themselves to embarrassing aspects of their life in the process narrating how a crime occurred.
The Torah is not be corrupted. There is no evidence to support this claim. Also, the Torah is ingrained in the hearts of the Jews from birth for generations as these verses will show:
“and thou shalt teach them diligently unto thy children, and shalt talk of them when thou sittest in thy house, and when thou walkest by the way, and when thou liest down, and when thou risest up.And thou shalt bind them for a sign upon thy hand, and they shall be for frontlets between thine eyes.And thou shalt bind them for a sign upon thy hand, and they shall be for frontlets between thine eyes.” Tanakh Bible Deuteronomy 6:6-8
“This book of the law shall not depart out of thy mouth, but thou shalt meditate therein day and night, that thou mayest observe to do according to all that is written therein; for then thou shalt make thy ways prosperous, and then thou shalt have good success.”Tanakh Bible Joshua1:8
“I will meditate in Thy precepts, and have respect unto Thy ways. I will delight myself in Thy statutes; I will not forget Thy word.” Tanakh Bible Psalms 119:15-16