It was at the word of Peter in the power of the Holy Spirit. He was no imposter. There is no blame. pay special attention to the phrase " hearing these words" which Ananias heard from Peter. Upon hearing the word of judgment from Peter both Ananias and Sapphira fell down physically dead. Biblical judgment from the mouth of an apostle in the power of the Holy Spirit. It is not murder. 5 But a certain man named Ananias, with Sapphira his wife, sold a possession. 2 And he kept back part of the proceeds, his wife also being aware of it, and brought a certain part and laid it at the apostles’ feet. 3 But Peter said, “Ananias, why has Satan filled your heart to lie to the Holy Spirit and keep back part of the price of the land for yourself? 4 While it remained, was it not your own? And after it was sold, was it not in your own control? Why have you conceived this thing in your heart? You have not lied to men but to God.” 5 Then Ananias, hearing these words, fell down and breathed his last. So great fear came upon all those who heard these things. 6 And the young men arose and wrapped him up, carried him out, and buried him. 7 Now it was about three hours later when his wife came in, not knowing what had happened. 8 And Peter answered her, “Tell me whether you sold the land for so much?” She said, “Yes, for so much.” 9 Then Peter said to her, “How is it that you have agreed together to test the Spirit of the Lord? Look, the feet of those who have buried your husband are at the door, and they will carry you out.” 10 Then immediately she fell down at his feet and breathed her last. And the young men came in and found her dead, and carrying her out, buried her by her husband. 11 So great fear came upon all the church and upon all who heard these things.
You are confusing roles. Peter did not do the sentencing. He just conducted the trial. They were found guilty. But for all anyone knows, they might have repented on the spot, and lived. But God acted independently to end their lives, which He had authority to do, and still does now among believers who have gone too far with some unresolved offense.
Think of those who fell ill, or died, as a result of being cavalier about their mistreatment of fellow believers in the context of the Lord’s Supper. This was also the act of God, as God has a right to do, but was never enacted by the sword or other instrumentality of men. Nor can one ever extrapolate from what God our Creator does to what we are also able to do as a matter of right. We are not God. Peter was not God. And he didn’t step on God’s jurisdiction. He never uttered a word about what should happen to Ananias and Saphira as a result of their sin. He clearly left that right where it belonged, in the hands of God.
Peace,
SR