World Wide Study Bible
a Bible passage
9. That if thou shalt, &c.—So understanding the words, the apostle is here giving the language of the true method of justification; and this sense we prefer (with Calvin, Beza, Ferme, Locke, Jowett). But able interpreters render the words, "For," or "Because if thou shalt," &c. [Vulgate, Luther, De Wette, Stuart, Philippi, Alford, Revised Version]. In this case, these are the apostle's own remarks, confirming the foregoing statements as to the simplicity of the gospel method of salvation.
confess with thy mouth the Lord Jesus—that is, probably, "If thou shalt confess Jesus [to be] the Lord," which is the proper manifestation or evidence of faith (Mt 10:32; 1Jo 4:15). This is put first merely to correspond with the foregoing quotation—"in thy mouth and in thine heart." So in 1Pe 1:10 the "calling of believers" is put before their "election," as that which is first "made sure," although in point of time it comes after it.
and shalt believe in thine heart that God hath raised—"that God raised"