Possible meanings are 1) this is the reason the man was made strong. Alternate translation: "Because of faith in his name" or 2) this is how the man was made strong. Alternate translation: "By faith in his name"
The word "his" refers to the Founder of life, Jesus. The abstract noun "faith" can be translated with the verb "believe." Possible meanings are 1) the lame man had faith in Jesus. Alternate translation: "Because he believed in Jesus name" or 2) Peter and John, and perhaps the lame man, had faith in Jesus. Alternate translation: "Because we believed in Jesus's name" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
Possible meanings are 1) this is the faith that Jesus enables people to have. Alternate translation: "The faith that comes from Jesus" or 2) this is faith in Jesus.