Charles Spurgeon Commentary Acts 2:41

"They then that received his word were baptized: and there were added [unto them] in that day about three thousand souls." — Acts 2:41 (ASV)

Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls.

They not only believed what he said, but they were glad to believe it; acknowledging that they had greatly sinned, they rejoiced that there was a promise which covered even their sin: Whosoever shall call on the name of the Lord shall be saved. Then, having repented and believed, they were baptized upon profession of their faith, according to the true Scriptural order.