Reference for Berakhot 37:1

ואי ס"ד דלא ידעי כי אמר להו מאי הוי אלא מאי דידעי למה לי' למימר להו לאחזוקי ליה טיבותא למשה

If thou shouldest imagine that they were not cognisant [of what transpires on earth], what use would it be to tell them ? On the other hand, if they were cognisant, what need was there for him to inform them ? To give the credit to Moses.

Jastrow