Gevurot Meyruach Hakodesh 2:38

And Kefa said to them, Make teshuva (repentance, turning from chet to HASHEM) and each of you submit to a tevilah of teshuva in the Shem of Yehoshua HaMoshiach, for the selichat avon of you, and you will receive the matanah of the Ruach Hakodesh.