Albert Barnes Commentary Acts 5:30

"The God of our fathers raised up Jesus, whom ye slew, hanging him on a tree." — Acts 5:30 (ASV)

Raised up Jesus. This refers to His resurrection.

Hanged on a tree. That is, on the cross, Galatians 3:13; 1 Peter 2:24; Acts 10:39; Acts 13:29. This is the substance of Peter's defense.

He begins with the great principle (Acts 5:29), which they could not contradict, that God ought to be obeyed rather than man. He then proceeds to state that they were convinced that God had raised up Jesus from the dead.

And since they had such decisive evidence of this, and were commanded by the authority of the Lord Jesus to be witnesses of that, and had constant evidence that God had done it, they were not at liberty to be silent. They were bound to obey God rather than the Sanhedrin and to make known everywhere the fact that the Lord Jesus had risen.

The remark that God had raised up Jesus, whom they had slain, does not seem to have been made to irritate or to reproach them, but mainly to identify the person that had been raised. It was also a confirmation of the truth and reality of the miracle. Of His death they had no doubt, for they had taken pains to certify it, John 19:31–34. It is certain, however, that Peter did not shrink from charging them with their guilt, nor did he take any pains to soften or mitigate the severe charge that they had murdered their own Messiah.