Sometimes the things God asks us to do seem difficult. Sometimes they seem dangerous. Sometimes they seem crazy. Sometimes they just do not make sense in the moment. Yet, God calls us to trust Him and obey - not the easiest thing to do.
Typically when you read Acts 9 the focus is on Saul's conversion. I do not know how many times I have read that chapter and not paid too much attention to the conversation that God had with Ananias in verses 11-17. Stop for a moment and put yourself in Ananias' shoes. God has just asked him to go the visit a man who is known for persecuting Christians. Just a few chapters earlier, the book of Acts records how Saul had been present and approved of the stoning of Stephen. The word from God to go and visit Saul cannot have been something that Ananias took lightly.
When God first told Ananias to go, he responded by reminding God of the reputation that his man had. Ananias had reason to be very afraid of this man. But, God still commanded Ananias to go and visit Saul, trusting God that Saul's conversion was the real deal. And so Ananias did obey and go.
I do not know about you, but that would be hard for me. As much as I know God can be trusted, I think I would have hesitated if I was in Ananias' shoes. Go and visit a known persecutor of Christians and pray for him! I do not think so. But, God says to trust Him and so you go anyways. That would be difficult. It would be scary. It would seem crazy.
Over and over again, Scripture is filled with accounts of God asking people to step out and follow Him in obedience - exercising their faith in Him. Many times these were in situations where it was hard to do so, yet, when people did step out in trust, God rewarded their obedience. Obeying what God tells us to do is not always easy. It can be hard. It can force us to face a fear we have. It can make us take a risk. But over and over again, we can see evidence of God's faithfulness when we do step out.
Scripture does not refer to the man spoken of in these verses again, but he is one of the examples of early believers acting on their faith. And faith is so much more than just head knowledge and agreeing with something. Faith does actually require us to take action. And God does keep His word to those believe Him and act in obedience to what He says.