romans 10:8 But what saith it? The word is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach; - Free Bible Online

      8. But what saith it? It saith--continuing the quotation from De 30:14.
      The word is nigh thee--easily accessible.
      in thy mouth--when thou confessest Him.
      and in thine heart--when thou believest on Him. Though it is of the law which Moses more immediately speaks in the passage quoted, yet it is of the law as Israel shall be brought to look upon it when the Lord their God shall circumcise their heart "to love the Lord their God with all their heart" (Ro 10:6); and thus, in applying it, the apostle (as OLSHAUSEN truly observes) is not merely appropriating the language of Moses, but keeping in the line of his deeper thought.
      that is, the word of faith, which we preach--that is, the word which men have to believe for salvation (compare 1Ti 4:6).

JFB.