In the midst of thee; better, is in the midst of thee (see note on Zephaniah 3:15). Is mighty; he will says; rather, a Mighty One who will save; LXX; ̓Ο δυνατὸς σώσει σε, "The Mighty One shall save thee."
This is the real ground of confidence: the Lord wills their salvation. He will rejoice over thee with joy, now that thy iniquity is purged, and thou art united again to him, as a chaste and comely bride (Isaiah 52:5; Jeremiah 32:41; Hosea 2:19).
He will rest (Hebrew, be silent) in his love. This is a human expression, denoting that perfect love which needs no outward demonstration. For the very greatness of his love God rests, as it were, in quiet enjoyment of it.
Some take it to mean that in his love for his people he is silent about, makes no mention of, past sins; but this seems less suitable, as this clause is merely an expansion of the preceding one. The Septuagint and Syriac Versions render, "He will renew thee in his love;" and Ewald has proposed to alter the present reading to, "He will do a new thing."
But there is no sufficient reason for making the change. With singing. Again he gives to his ineffable love outward expression. The LXX. paraphrases accurately, "He will rejoice over thee with delight as on a day of festival" (Isaiah 65:19).