Being a Jew the beggar knows that his healing is a miracle that has come from God, which is why he wants to go and praise God in the temple. This would be the first time that he is allowed to enter the temple proper, seeing as his disability would have excluded him in the past (see Leviticus 21:17–20; 2 Samuel 5:8).1 Since he also held on to Peter and John (Acts 3:11), it is likely that he wanted to learn more from them about Jesus.
8 And leaping up he stood and began to walk, and entered the temple with them, walking and leaping and praising God.