I can 'prove' that my mind exists, and I have faith in it's capacity to prove it's own existence.
We atleast have faith in our own capacities, even in trying to justify our own capacities. Faith then, is prior to, and necessary for, proof.
In Augustinian terms, 'faith seeking understanding'.
In Anselm's words, 'We believe in order to understand'.
Jesus had faith in the Father, even though He knew that the Father would provide for all His needs. Faith in God, contrary to atheistic opinion, does not mean unproved theism. Faith encompasses more than the belief that God exists. Faith, in theological terms, is the union between Christ and someone who has peace with God, ie., someone upon whom there is no wrath due to sin.
kind regards