As for thee also. The prophet addresses the daughter of Zion, the covenant people (comp. Zechariah 9:10, Zechariah 9:13). "Also" is inserted to intimate that this deliverance is given in addition to the blessings promised in the two preceding verses.
All who are living far from their native Zion are invited to come to her and partake of her good things. By (because of) the blood of thy covenant. The covenant is that made at Sinai, sealed and ratified by blood (Exodus 24:4-8), which still held good, and was the pledge to the nation of deliverance and help.
This was a token of that everlasting covenant sealed with the blood of Christ, by which God's people are delivered from the bondage of sin (comp. Matthew 26:28; Hebrews 9:15; Hebrews 10:14-23; Hebrews 13:20).
I have sent forth; I send forth—the prophetic perfect. The Greek and Latin Versions render, "thou sentest forth," not so correctly. Thy prisoners. Those members of the nation who were still oppressed or captives in foreign lands, as Babylon and Egypt (comp.
Obadiah 1:20; Joel 3:6, etc.; Amos 1:6, Amos 1:9, etc.). The pit wherein is no water. "Pit," or cistern, is a common name for a prison (Genesis 40:15; Exodus 12:29; Jeremiah 37:16). The absence of water may be notified either to imply that the tortures of thirst were added to the horror of the situation, or to intimate that the prisoners were not hopelessly drowned therein.
We Christians see in this paragraph a figure of the redemption of a lost world by the blood of Christ.