The sinner’s prayer most often finds its advocates in the corner of those who espouse the grace only and faith only doctrines.
These particular doctrines basically say that an individual can personally do nothing to “earn” his or her salvation, hence the need for repentance, confession, baptism and even faithfulness becomes a “fruit” of salvation rather than “seeds” which lead to it.
But isn’t it funny how those who teach that there is “nothing that a person can do to earn their salvation” also teach that the same person “must” say a prayer to be saved?
“Do you not know that to whom you present yourselves slaves to obey, you are that one’s slaves whom you obey, whether of sin leading to death, or of obedience leading to righteousness? But God be thanked that though you were slaves of sin, yet you obeyed from the heart that form of doctrine to which you were delivered.” (Romans 6:16-17)