Albert Barnes Commentary John 14:11

"Believe me that I am in the Father, and the Father in me: or else believe me for the very works` sake." — John 14:11 (ASV)

Believe me, and so forth. Believe My declarations that I am in the Father, and the Father in Me. There were two grounds on which they might believe: one was His own testimony, the other was His works.

Or else. If credit is not given to My words, let credit be given to My miracles.

For the very works' sake. On account of the works; or, be convinced by the miracles themselves. Either His own testimony was sufficient to convince them, or the many miracles He had performed in healing the sick, raising the dead, and so on.