10:13 whosoever shall call. See notes on Acts 2:21, where the same verse is quoted (Joel 2:32). Paul had been stressing God’s electing sovereignty in Romans 9; here he again stresses human responsibility. Both are true.
10:15 it is written. This testimony is found in Isaiah 52:7. Note also Ephesians 6:15: “[having] your feet shod with the preparation of the gospel of peace.” A similar figure is used in Nahum 1:15.
10:16 Esaias saith. Isaiah 53:1 is quoted here. Although the gospel of peace with God is, indeed, “glad tidings” to all who will believe, most will refuse to believe.
10:17 by the word. In this verse, “word” means, literally, “saying” (same as in Ephesians 6:17, referring to “the sword of the Spirit”). That is, not just the Bible in general, but each individual “saying” is vital to the full understanding of God’s plan. In some manuscripts, “the word of God” is replaced by “the word of Christ.” Since Christ is God, the effect is the same.