If thou confess with thy mouth Jesus as Lord, and believe in thy heart that God raised him from the dead, thou shalt be saved: End of story. ...
Romans 10:9 is offered to many people seeking salvation, and when they sincerely confess Jesus is their Lord, they are told that they have received salvation !
However, that verse is written in a letter to the church at Rome, are they not already saved yet? Of course they are! You cannot be in Christ’s body (“the church”) without having already received salvation.
The verse means to agree with what Jesus said (“confess” is homo-logos in the Greek, and means to speak the same word) and to believe that those in Him have his Life. So, having already received the Spirit, they are to live His Life, not return to ways of "the flesh".
This is seen from the previous verse:-
v8: “. . . The word is nigh thee, even in thy mouth, and in thy heart . . . “
Is the word in the heart of unsaved people? No, only Holy Spirit-indwelt people have this:-
“This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them"
(Heb. 10:16; see also 2 Cor.3:3)
The unsaved natural man can believe that the bible is true, but he does not have the Life it describes until he receives the Holy Spirit (1 Cor. 2:9-14, John 3:3-8).
The way of salvation had already been laid down on the day of Pentecost by the words of Peter as the perfect answer to the question... ‘Men and brethren, what shall we do?’
Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost. For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call.
Much of the previous passage defines the receiving of the Holy Spirit :-
“they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance . . . (Jesus) being by the right hand of God exalted, and having received of the Father the promise of the Holy Ghost, he hath shed forth this, which ye now see and hear.”
Jesus said that is how to receive Him and His salvation (see John 3:3-8, 14:17, 20; Mark 16:15-20; Titus3:5-6), and interestingly, Jesus made a point of saying that it’s not what we say about ourselves, it’s God’s witness we should look for:-
“If I bear witness of myself, my witness is not true. There is another that beareth witness of me”
A voice was heard when Jesus received the Holy Spirit.
The Roman Christians had already all been baptised by full immersion and had all received the Spirit with the ability to pray in tongues:-
Romans 6:3-4: Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death? Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
8:15-16: For ye have not received the spirit of bondage again to fear; but ye have received the Spirit of adoption, whereby we cry, Abba, Father. The Spirit itself bears witness with our spirit, that we are the children of God.
If the context can really be ignored in order to obtain personal salvation, you might as well go straight to verse 13 which says:-
"whosoever shall call upon the name of the Lord shall be saved."
Just tell the people that they only have to say the word "Jesus" and they are born again and saved - They don't even have to confess or believe !
(In fact, “calling on the name of The Lord” to receive salvation means to pray to receive the Holy Spirit - see Acts 22:16, 1 Cor. 6:11)
So we see here in this letter that when Paul wrote to the Christians at Rome, he had acknowledged that they had already all received their salvation, the new Life, and was telling them how to stay saved, i.e. free from the power of sin, by living and relying on that new Life.
Beware the warnings in scripture of ‘another gospel’. Romans 10:9 is how to stay saved, after you have already repented, been baptised and received the Holy Spirit with the evidence of speaking in tongues;
it is not the gospel of how to be saved in the first place!