Those who gladly received the word of Peter in Acts 2,  were baptized.  A group of about 3000 on that inaugural day of the New Testament church had responded to the instructions of Peter in Acts 2:38.
But those who experienced Acts 2:38,  needed to continue steadfastly.  
To all who experience Acts 2:38,  there is more to being saved than a once in lifetime experience.  Salvation must become a way of living.