A.T. Robertson Commentary John 5:46

"For if ye believed Moses, ye would believe me; for he wrote of me." — John 5:46 (ASV)

Ye would believe me (επιστευετε αν εμο). Conclusion of condition of second class (determined as unfulfilled) with imperfect indicative in both protasis and apodosis and αν in apodosis. This was a home-thrust, proving that they did not really believe Moses.

For he wrote of me (περ γαρ εμου εκεινος εγραψεν). Deuteronomy 18:18f. is quoted by Peter (Acts 3:22) as a prophecy of Christ and also by Stephen in Ac 7:37. See also Joh 3:14 about the brazen serpent and 8:56 about Abraham foreseeing Christ's day. Jesus does here say that Moses wrote concerning him.