en_tn/rom/12/06.md

We have different gifts according to the grace that was given to us

Paul speaks of believers' different abilities as being free gifts from God. You can translate this in an active form. Alternate translation: "God has freely given each of us different abilities to do things for him" (See: rc://en/ta/man/jit/figs-metaphor)

let it be done according to the proportion of his faith

Possible meanings are 1) "let him speak prophecies that do not go beyond the amount of faith God has given us" or 2) "let him speak prophecies that agree with the teachings of our faith."