Romans 10:9 (BSB)

that if you confess with your mouth, “Jesus is Lord,” and believe in your heart that God raised Him from the dead, you will be saved.

From Romans 10. Also in the ESV.

Commentary on Romans 10:9

• John Calvin (Reformed), Calvin's Commentaries on Romans 10:9: 9. That if thou wilt confess, etc. Here is also an allusion, rather than a proper and strict quotation: for it is very probable that Moses used the word mouth, by taking a part for the whole, instead of the word face, or sight.
• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Romans 10:1-11: The scope of the apostle in this part of the chapter is to show the vast difference between the righteousness of the law and the righteousness of faith, and the great pre-eminence of the righteousness of faith above that of the law; that he might induce and persuade the Jews to believe in Christ, aggravate the folly and sin of those that refused, and justify...
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on 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...
• Albert Barnes (Presbyterian), Barnes' New Testament Notes on Romans 10:9: Verse 9. That if thou shalt confess. The word here rendered confess--(ομολογησης)--is often rendered profess. , "Then will I profess to them I never knew you." Tit 1:16; 3:14; Ro 1:22; , etc. It properly means, to speak that which agrees with something which others speak or maintain.