Mark 16:16 He that believeth and is baptized shall be saved; but he that believeth not shall be damned.
Acts 2:38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
Acts 2:41 Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls.
Acts 8:12 But when they believed Philip preaching the things concerning the kingdom of God, and the name of Jesus Christ, they were baptized, both men and women. 13 Then Simon himself believed also: and when he was baptized, he continued with Philip, and wondered, beholding the miracles and signs which were done.
Acts 10:47 Can any man forbid water, that these should not be baptized, which have received the Holy Ghost as well as we? 48 And he commanded them to be baptized in the name of the Lord. Then prayed they him to tarry certain days.
Acts 19:3 And he said unto them, Unto what then were ye baptized? And they said, Unto John’s baptism. 4 Then said Paul, John verily baptized with the baptism of repentance, saying unto the people, that they should believe on him which should come after him, that is, on Christ Jesus. 5 When they heard this, they were baptized in the name of the Lord Jesus.
Gal. 3:27 For as many of you as have been baptized into Christ have put on Christ.
Baptism is essential to salvation. Mark 16:16 clearly states the he that believes and is baptized will be saved.
Peter when preaching on the day of Pentecost, told all those in earshot, in front of all the other disciples of Christ (Apostles) that they must repent, be baptized and receive the Holy Ghost with the evidence of speaking in tongues.
3000 souls were added to them (that is, made Christians) when they received the word and were baptized.
All throughout the book of Acts, we find the Apostles baptizing new converts in the name of Jesus. Jesus is the name that holds authority and power, and in His name we are to do all things (pray, baptize, preach, etc...)