John Gills Exposition of the Bible Commentary

Verse 9 (Romans 10:9)

That if thou shalt confess with thy mouth the Lord Jesus ,.... That is, if a man shall make a good, sincere, and hearty confession to God, before the church and people of God, and before the world, that Christ is his Lord and Saviour, whom he desires to serve, and to be saved by; and this as arising from a comfortable experience of the grace of God in his soul, and from a true faith in Christ in his heart, wherefore it follows,

and shall believe in thine heart, that God hath raised him from the dead, thou shalt be saved ; for this article of Christ's resurrection includes the several other articles of faith: it supposes his death, and that supposes his life, and the obedience of it; and his life implies his being here on earth, and that his coming down from heaven to do the will of his Father; and this is the rather mentioned, which is here ascribed to God the Father, though not to the exclusion of the Son and Spirit, because that Christ is risen again for our justification, with which true faith is principally concerned; for such a faith is intended, not which lies in a mere assent to the truth of this, or any other article of the Christian religion; but which is concerned with Christ for righteousness, life, and glory; and with such a faith salvation is certainly and inseparably connected.

- John Gills Exposition of the Bible Commentary