Romans 10:10 - Joseph Benson’s Commentary on the Old and New Testaments

For with the heart Not with the understanding only; man believeth unto righteousness So as to obtain justification, regeneration, and holiness, in all its branches; and with the mouth confession is made unto salvation So as to obtain eternal salvation. For if we so believe in Christ as to become truly righteous, and manifest that we are so by confessing him to be the Messiah, the Son of God, the Saviour of the world, when such a confession might deprive us of our property, our liberty, and our lives, we must, of course, love him better than any or all of these things; and therefore we willingly part with them for his sake. And being thus crucified to the world, and all visible and temporal things, our affections will be set on things above, where Christ sitteth at the right hand of God: and consequently, when he shall appear we shall appear with him in glory. “In the first ages, the spreading of the gospel depended, in a great measure, on Christ's disciples confessing him openly before the world, and on their sealing their confession with their blood. Hence Christ required it, in the most express terms, and threatened to deny those who denied him, Matthew 10:32-33; 1 John 4:15. The confessing Christ being so necessary, and at the same time so difficult a duty, the apostle very properly connected the assurance of final salvation therewith; because it was the best evidence which the disciple of Christ could have of his own sincerity, and of his being willing to perform every other act of obedience required of him. There is a difference between the profession and the confession of our faith. To profess is to declare a thing of our own accord; but to confess is to declare a thing when asked concerning it. This distinction Cicero mentions in his oration Pro Cecinna.” Macknight.