According to the book of Romans 10, salvation comes by believing in the Lord Jesus and confessing His Lordship and that only He can save. One cannot be said to be genuinely saved if he meets one of these conditions but omits the other. When we confess Christ as Saviour, we believe in who He is and what He can accomplish. It is a declaration that we are no longer of the unbelieving world but have become children of the Most High. This action usually precedes water baptism, whereby we identify ourselves with the family of God on Earth - the church.
However, the process of salvation is not just about believing and confessing. It begins with repentance of old ways and making a decision to renounce them or forsake them. Proverbs 28:13 tells us that those who confess and forsake their sins will receive mercy (pardon and forgiveness). The new converts in the above scripture confessed their evil deeds and renounced them, having been convicted by the Spirit after hearing the word. They must have regretted their actions of wickedness, and as a sign of surrender to Jesus, they confessed their old ways. Though it is not mandatory and not a requisite to salvation, telling others what we were before we became saved can help us in witnessing Christ to unbelievers.

Thank You, Jesus, for saving me and for being the Lord of my life. Thank You for showing me mercy by granting me forgiveness for my numerous sins. I bless You for counting me worthy to be a member of Your kingdom on Earth. I pray that I will not lose my salvation to a life of sin. In the grace that I receive, I pray that I won't backslide into my old ways. Help me reject every suggestion of the devil to go back to my old way of life and overcome every temptation to renounce Your name.
In Jesus's name I pray. Amen.