[This letter is from] Paul, an apostle of Christ Jesus by the will of God, according to [the ministry of proclaiming] the promise of never ending life, which is [obtained] through [fellowship with] Christ Jesus.

If we prove to be unfaithful [i.e., to our commitment to Christ], He [still] remains faithful [to His word], for He cannot deny Himself. [Note: This verse refers to Christ remaining true to His promise of either accepting or rejecting us. See Matt. 10:32-33].