Jamieson, Fausset & Brown

Drop--namely, the fertilizing rain (Psa 65:12). skies--clouds; lower than the "heavens." righteousness--that is, the dews of the Holy Spirit, whereby "righteousness" shall "spring up." (See latter end of the verse). earth--figuratively for the hearts of men on it, opened for receiving the truth by the Holy Ghost (Act 16:14). them--the earth and the heavens. HORSLEY prefers: "Let the earth open, and let salvation and justice grow forth; let it bring them forth together; I the Lord have created him" (Isa 45:13). MAURER translates, "Let all kinds of salvation (prosperity) be fruitful" (Psa 72:3, Psa 72:6-7). The revival of religion after the return from Babylon suggests to the prophet the diffusion of Messiah's Gospel, especially in days still future; hence the elevation of the language to a pitch above what is applicable to the state of religion after the return.