There are those who say that all you have to do is ask Jesus into your heart and you will be saved. Those are the words of man. The words of man should always be tested with the Words of God. The Word of God is the Bible, so what does the Bible say about that claim?
God says, “Whoever believes and is baptized will be saved, but whoever does not believe will be condemned.” (Mark 16:16 NIV) The verse seems somewhat softened by the second part of it. If you do not want to believe the first part, then because it does not say ‘Those who do not believe and are not baptized will be condemned’ one might think baptism is not necessary. If that is the way you read the verse, then ask yourself why God would include baptism in the second part of the verse? If one doesn’t believe in the sacrifice of Jesus then why in the world would they allow someone to baptize them? It would be redundant to repeat baptism in the second part of the verse.
Those that claim that you only must say Jesus come into my heart and that will save you must do something with baptism, because God’s Word says much about baptism and therefore they realize it is necessary to somehow nullify it. So, they make the claim that it is only symbolic in nature! Again, what does the Word of God say? Does it agree that it is only symbolic, or does it say baptism actually has the power to change someone?
“(All the people, even the tax collectors, when they heard Jesus’ words, acknowledged that God’s way was right, because they had been baptized by John. But the Pharisees and experts in the law rejected God’s purpose for themselves, because they had not been baptized by John.)” (Luke 7:29&30 NIV)
You see that baptism is not symbolic, but powerful to add understanding to those who believe and are baptized.
If that animal Satan can convince you that baptism is not necessary then he has accomplished his goal, which is to deceive you and cause you to be condemned as Mark 16:16 states.
Jesus told his disciples go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit (Mat 28:19 NIV). If you are listening to some one who is telling you that all you have to do is invite Jesus into your heart, then he or she is not doing what Jesus said to do and they are in great danger and they are also placing you in danger as well.
Baptism makes straight the way for the Lord. It washes away sin so the one without sin (Jesus) can become one with one that has, or rather had sin. It is necessary so that Jesus does not become unequally yoked to someone who has sin. That is not to say that we will no longer sin, but for an instant we are clean and at that instant the Spirit of life can become one with us and not violate the Law.
Go, be baptized and be saved.