That which hath been is now; so Septuagint; "That which hath been made, the same remaineth" (Vulgate); better, that which hath been, long ago it is; i.e. was in existence long before. The thought is much the same as in Ecclesiastes 1:9, only here it is adduced not to prove the vanity and endless sameness of circumstances, but the orderly and appointed succession of events under the controlling providence of God.
That which is to be hath already been. The future will be a reproduction of the past. The laws which regulate things change not; the moral government is exercised by him who "is, and was, and is to come" (Revelation 1:8), and therefore in effect history repeats itself; the same causes produce the same phenomena.
God requireth that which is past; literally, God seeketh after that which hath been chased away; Septuagint, "God will seek him who is pursued ( τὸν διωκόμενον);" Vulgate, "God reneweth that which is passed (instaurat quod abiit)."
The meaning is—God brings back to view, recalls again into being, that which was past and had vanished out of sight and mind. The sentence is an explanation of the preceding clauses, and has nothing to do with the inquisition at the day of judgment.
Hengstenberg has followed the Septuagint, Syriac, and Targum, in translating, "God seeks the persecuted," and seeing herein an allusion to the punishment of the Egyptians for pursuing the Israelites to the Red Sea, or a general statement that God succors the oppressed.
But this idea is quite alien to the intention of the passage, and injures the coherence.