Matthew 12:38-40 (NIV)
38 Then some of the Pharisees and teachers of the law said to him, “Teacher, we want to see a sign from you.” 39 He answered, “A wicked and adulterous generation asks for a sign! But none will be given it except the sign of the prophet Jonah. 40 For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth.
Would not it be impossible to fulfill this prophecy and indeed many others without his sacrifice? To which your theory that his physical death indicates he was a false prophet can not logically be applied.
Only relevant if one accepts a priori the claims of the New Testament and the traditions of the Church about Jesus.
Deuteronomy 17
8 If there arise a matter too hard for thee in judgment, between blood and blood, between plea and plea, and between stroke and stroke, being matters of controversy within thy gates: then shalt thou arise, and get thee up into the place which the Lord thy God shall choose;
9 And thou shalt come unto the priests the Levites, and unto the judge that shall be in those days, and enquire; and they shall shew thee the sentence of judgment:
10 And thou shalt do according to the sentence, which they of that place which the Lord shall choose shall shew thee; and thou shalt observe to do according to all that they inform thee:
11 According to the sentence of the law which they shall teach thee, and according to the judgment which they shall tell thee, thou shalt do: thou shalt not decline from the sentence which they shall shew thee, to the right hand, nor to the left.