The power of the church comes from the Holy Spirit. God knows us well enough to know that just seeing something is not enough to convict us of its truth. Think about the Old Testament. How many times did the Israelites see, or hear, irrefutable proof of God yet, as time passes, they forgot or ignored the truth that they knew? Without the Holy Spirit living in us, we only have good feelings about the gospel and as we all know, good feelings can fade because they are based on emotions not convictions. Think of it this way, what do you think the divorce rate would be if every married person had a living spirit inside of them reminding them daily of their spouse’s love for them, convicting them daily of their love for their spouse? Christians have the Holy Spirit living inside of them reminding them daily of God’s love for them, convicting them daily of their love for God. The key is listening to that Spirit and drawing power from it.