O ye Corinthians, our mouth is open unto you, our heart is enlarged.
Mouth is open unto you. I use no concealment, as some have insinuated (2 Corinthians 4:2), but all openness of speech to you as to beloved friends. Hence, he adds, "O ye Corinthians" (cf. Philippians 4:15). His enlargement of heart toward them (2 Corinthians 7:3) produced, and in turn was promoted by, his openness of mouth (Ezekiel 33:22) -
i.e., unreserved expression of his desire to commend himself and his office to them (2 Corinthians 6:3-10), that they might accept his message (2 Corinthians 6:1-2). As an unloving man is narrow in heart, so the apostle's heart is enlarged by love, so as to have room for all his converts at Corinth, not only with their graces, but with their shortcomings (cf. 1 Kings 4:29; Psalms 119:32; Isaiah 60:5). Love, like heat, expands.