"Delivered" here is a metaphor for "brought." AT: "they brought to the believers in the churches there" (See: [[rc://en/ta/man/translate/figs-metaphor]]).
# that had been written by the apostles and elders in Jerusalem
This can be stated in active form. AT: "that the apostles and elders in Jerusalem had written" (See: [[rc://en/ta/man/translate/figs-activepassive]])
# the churches were strengthened in the faith and increased in number daily
This can be stated in active form. AT: "The believers became stronger in their faith, and there were more and more people becoming believers every day" (See: [[rc://en/ta/man/translate/figs-activepassive]])
This speaks of helping someone to believe more confidently as if it were making them physically stronger. (See: [[rc://en/ta/man/translate/figs-metaphor]])