For by grace you have been saved through faith and this is not your own doing. -- Ephesians 2:8
This includes special ceremonies like the "sinner's prayer" or "Baptism".
No, every believer should get baptized, because:
- It releases believers from the legal requirements of the laws. (Colossians 2:11-23, Romans 6:14)
- It releases believers from sin by the burial of the old life (Acts 22:16, Acts 2:38)
- It is converts believers into new people by giving them a new life (Colossians 2:12-14, 2 Corinthians 5:17, Romans 6:3-14, Acts 19:4)
- The water is one of the witnesses that testifies that believers' sins are forgiven. (1 John 5:6-7)
- It is a physical sign of salvation for good conscience. (1 Peter 3:21)
- It is a requirement to enter the kingdom of God. (John 3:5)
- It restores righteousness with God (Matthew 3:15) and fellow believers. (1 Corinthians 12:13)
It is the example set by Christ Himself:
We were buried therefore with him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life. -- Romans 6:4 (ESV)
Baptism usually goes together with repentance and not separate. This is how the disciples and the apostles understood it and how Jesus taught his followers. This is to reduce the risk of:
- still living under a curse (of the law)
- still being stuck in the bondage of addictions or temptations of sin
- you won't notice a difference in your life
- doubt in your salvation
- feeling guilty (disobedient)
- being excluded from God's kingdom (outside God's protection)
- live unrighteous (disconnected from God)
When a righteous person turns away from his righteousness and does injustice, he shall die for it; for the injustice that he has done he shall die. -- Ezekiel 18:26 (ESV)
Let's have a look at an example of someone who converted just before he died:
Then one of the criminals who was hanged blasphemed Him, saying, "If You are the Christ, save Yourself and us."
But the other, answering, rebuked him, saying, "Do you not even fear God, seeing you are under the same condemnation? And we indeed justly, for we receive the due reward of our deeds; but this Man has done nothing wrong."
Then he said to Jesus, "Lord, remember me when You come into Your kingdom."
And Jesus said to him, "Assuredly, I say to you today, you will be with Me in paradise."
-- Luke 23:39-43
In this case the thief got saved because:
- Believed in Jesus (Acts 16:31; Romans 3:28)
- He repented with a simple prayer "Lord, remember me when You come into Your kingdom."
- Jesus forgave him, because he knew his heart (it was not quick "sinner's prayer" to impress Jesus)
Baptism in this case was not possible for him, yet Jesus said: "you will be with Me in paradise".
When people are lying on their death beds at the final hours of their lives, it would be unpractical and unnecessary to panic or to rush to a river or something to try to get them baptized before they physically die.
But is this is no new doctrine or relaxation of the Jesus's commands. If you have the strength, time and access to water, you have no excuse not to get baptized.