I had the privilege of watching a friend's child be baptized this past Sunday.
Each time I witness this event, I am gladdened. Yes, "gladdened" is a real word. I look forward to the day when, God willing, my children get dunked.
Baptism is that public outward sign that a person has, "Believe(d) on the Lord Jesus Christ..." and is saved.
The Philippian Jailer Converted
About midnight Paul and Silas were praying and singing hymns to God, and the prisoners were listening to them, and suddenly there was a great earthquake, so that the foundations of the prison were shaken. And immediately all the doors were opened, and everyone's bonds were unfastened. When the jailer woke and saw that the prison doors were open, he drew his sword and was about to kill himself, supposing that the prisoners had escaped. But Paul cried with a loud voice, “Do not harm yourself, for we are all here.” And the jailer called for lights and rushed in, and trembling with fear he fell down before Paul and Silas. Then he brought them out and said, “Sirs, what must I do to be saved?” And they said, “Believe in the Lord Jesus, and you will be saved, you and your household.” And they spoke the word of the Lord to him and to all who were in his house. And he took them the same hour of the night and washed their wounds; and he was baptized at once, he and all his family. Then he brought them up into his house and set food before them. And he rejoiced along with his entire household that he had believed in God. (Act 16:25-34)