Number 5 on the list of things that need to happen in order to be saved is the need of baptism:
There are many views on how this needs to be accomplished; infant baptism, adults only baptism by immersion, baptism by sprinkling, to name a few. I will give my view on this issue....and will try to make it as brief as I can without (hopefully) oversimplifying it. And I hope you will do your own research on this complex topic by using the Bible as your source main source of information.
Let's first begin with reviewing the above Bible verses (all Bible verses in this post will be from the ESV version):
Matthew 28:19-20 Go therefore and make disciples of all nations,
baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age."
Mark 16:16 Whoever believes
and is baptized will be saved, but whoever does not believe will be condemned.
Acts 2:38 And Peter said to them, "Repent
and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit.
Acts22:16 And now why do you wait? Rise and be baptized and wash away your sins, calling on his name.'
We can also add to the above list the passages which tell of Jesus being baptized by John the Baptist even though He being perfect needed no forgiveness of sins....and there is this one with Philip and the Ethiopian Eunuch:
Acts 8:36-37 And as they were going along the road
they came to some water, and the eunuch said,
"See, here is water! What prevents me from being baptized?" And he commanded the chariot to stop, and they both went down into the water, Philip and the eunuch,
and he baptized him.
There are the exceptions to the rule, such as the thief that hung on the cross beside Jesus who received no baptism (that we know of, the ritual of baptism was already in use at the time of Christ). Some take this to mean that the water baptism is a physical type for the spiritual effect of having our sins washed away by the baptism of the Holy Spirit.
1John 5:4-8
For everyone who has been born of God overcomes the world.
And this is the victory that has overcome the world—our faith.
Who is it that overcomes the world except the one who believes that Jesus is the Son of God? This is he who came by water and blood—Jesus Christ; not by the water only but by the water and the blood.
And the Spirit is the one who testifies, because the Spirit is the truth.
For there are three that testify:
the Spirit
and the water
and the blood;
and these three agree.
My own view on this is that water baptism is necessary as part of the believer's testimony of the truth of his conversion. Whether the thief on the cross was or was not baptized in water is irrelevant to your and my circumstances. We are not hanging on a literal wooden cross which makes it impossible to perform such a simple task in obedience to following Jesus. Some say it must be in "the name of the Father, Son and Holy Ghost" (Matthew 28:19) some say in the name of Jesus only (Acts 2:38), the important matter is that you confess your sins and be baptized in the sacrifice of God in Christ for the remission of sins, with the realization of the incredible price Jesus paid in order to wash those sins away having died to self, being born anew in the Spirit, and then beginning a new life that is alive in Christ.
I hope this little series on salvation basics was helpful, but please do your own research, read the above verses in their full context by reading the entire books of the Bible carefully. There is so much there that cannot be summed up in a blog post. I pray that you study to show yourselves approved, and receive the full blessings from seeking the Lord with all your hearts.