Romans 10:9
That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.
Salvation comes by confessing with the mouth Jesus as Lord and believing in the heart that God raised Him from the dead. That same confession and heart-belief in the risen Jesus is how salvation is received, with faith leading to righteousness and confession to salvation. The word of faith is near, in the mouth and in the heart. Christ, the source of everlasting life, is near rather than distant, so no one must ascend to heaven to bring Him down or descend to the deep to bring Him up.
Salvation does not require payment, money, pilgrimage, costly or painful journeys, or other human efforts. Receiving salvation calls for trusting Christ as a personal Saviour, the sinner's own Saviour and only hope. Receiving the near word calls for obedience to His Word and doing His Word. Faith in Christ is the fallen world's only hope.
The belief and confession described mean more than casual belief or mere intellectual agreement that Christ came and died to save humanity. Saving faith is sincere, intelligent trust that clings to the Saviour, grasps God's provision, engages the affections, and directs the life. Heart faith places the affections on Christ, brings the understanding under the Holy Spirit's control, and shapes the character after Christ's likeness. Such faith rests on the merit of the crucified and risen Saviour and purifies the soul. It is living faith that works through love.
Faith leads to righteousness, and confession leads to salvation. Confessing the Lord Jesus means openly acknowledging Him even when doing so brings danger or threat, without fear. Luther's willingness to face death while confessing Jesus illustrates this open, fearless confession under threat.