We ask, what is baptism a sign of? It is said that baptism is an outward sign of inward grace, a sign that the Holy Spirit has quickened the heart, implanted faith, and granted salvation. Is this true?
In this lesson we need to keep in mind that the Bible uses the word "sign" in two ways:
Baptism is a sign in the first of those senses (but please note that baptism is not just a sign or symbol.)
Our first two points below look at faith in Christ —the source of faith and the sign of faith.
So then faith comes by hearing, and hearing by the word of God (Romans 10:17 NKJV).
Faith comes when people listen to the gospel or read the written word (Ephesians 1:13).
By this word of the gospel, God opens the good hearts to accept that word, to believe and obey it as Lydia did (Acts 16:14-15).
Some people say that God speaks directly to people of his choosing and gives them faith as a gift —which they could not receive just by listening to and considering the word of the gospel revealed in the scriptures.
If God is giving faith to some and leaving others without it, doesn't that make him "a respector of persons"? (Acts 10:34-35)
No, God does not speak the gospel to some and not others. He revealed the word for everyone to hear and believe. Of course many will refuse to listen but that's not God’s fault or desire.
Fight the good fight of faith, lay hold on eternal life, to which you were also called and have confessed the good confession in the presence of many witnesses (1Timothy 6:12 NKJV).
The gospel is the power of God to bring about salvation by faith (Romans 1:16). From the outset, that faith in one’s heart must be confessed with the mouth unto salvation (Romans 10:8-10). That testimony is evidence of faith and is, in that sense, a sign of faith.
Now we can answer the question, What is Baptism a sign of?"
Or do you not know that as many of us as were baptized into Christ Jesus were baptized into His death? 4Therefore we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in newness of life. 5 For if we have been united together in the likeness of His death, certainly we also shall be in the likeness of His resurrection, 6 knowing this, that our old man was crucified with Him, that the body of sin might be done away with, that we should no longer be slaves of sin (Romans 6:3-6 NKJV).
Even if it were true that baptism is evidence (and in that sense a sign) of faith, that's no reason to dismiss baptism as unnecessary for salvation.
Paul makes baptism a sign or "likeness" of the death, burial, and resurrection of Jesus. That is a far better answer for what baptism signifies. The assertion that baptism is a sign of faith is not supported by scripture.
But Paul goes further than that. He says believers are...
(Romans 6:3-6 fully quoted earlier)
We cannot be saved outside of Christ. We need to be baptized into him and into his death, buried with him and raised up with him in baptism, united together with him in the likeness of his death.