God's power is now toward us and works in us. The Spirit will often use the Word we have hidden in our hearts. Just a little of God's Word will enrich us. We bear fruit to God as a result of being with Him. Whatever fruit comes out of us is the result of what is in our hearts.
Fruit is the result of faith.
They took note of Peter and John by seeing their fruit, concluding they had been with Jesus. Once we were deaf, even though we have ears, and blind even though we had eyes. The Lord calls to the part of us in which He has done a good work. We are called to not only listen, but to meditate on what we have heard. When the lord has our ears, He will give us promises to give us incentive.