This is the most important question you will ever consider in this life.
Romans 10:17 So then faith cometh by hearing, and hearing by the word of God.
Matthew 7:24-27 Therefore whosoever heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock: And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock. And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand: And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.
Mark 16:15-16 And he said unto them, Go ye into all the world, and preach the gospel to every creature. He that believeth and is baptized shall be saved; but he that believeth not shall be damned.
Not Faith Only - James 2:24 Ye see then how that by works a man is justified, and not by faith only.
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.
Luke 13:3 I tell you, Nay: but, except ye repent, ye shall all likewise perish.
Matthew 10:32-33 Whosoever therefore shall confess me before men, him will I confess also before my Father which is in heaven. But whosoever shall deny me before men, him will I also deny before my Father which is in heaven.
Acts 8:36-37 And as they went on their way, they came unto a certain water: and the eunuch said, See, here is water; what doth hinder me to be baptized? And Philip said, If thou believest with all thine heart, thou mayest. And he answered and said, I believe that Jesus Christ is the Son of God.
Baptism commanded - Acts 10:48 And he commanded them to be baptized in the name of the Lord. Then prayed they him to tarry certain days.
For the remission of sins - 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.
Baptism saves - 1 Peter 3:21 The like figure whereunto even baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:
Baptism is a burial (immersion) - Romans 6:3-4 Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death? Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
Baptism requires much water - John 3:23 - And John also was baptizing in Aenon near to Salim, because there was much water there: and they came, and were baptized.
Baptism requires going down into the water - Acts 8:38 - And he commanded the chariot to stand still: and they went down both into the water, both Philip and the eunuch; and he baptized him.
Baptism gets us into Christ - Galatians 3;26-27 For ye are all the children of God by faith in Christ Jesus. For as many of you as have been baptized into Christ have put on Christ.
Baptism gets us into the body (Church) - 1 Corinthians 12:13 For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.
Revelation 2:10 - ... be thou faithful unto death, and I will give thee a crown of life.
The Scriptures teach against "once saved , always saved" - James 5:19-20 Brethren, if any of you do err from the truth, and one convert him; Let him know, that he which converteth the sinner from the error of his way shall save a soul from death, and shall hide a multitude of sins.