At midnight I will rise to give thanks unto you because of your righteous judgments.
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Augustine of Hippo
AD 430
60. "At midnight," he saith, "I rise to give thanks unto Thee: because of Thy righteous judgments" (ver. 62). This very fact, that the bands of the ungodly surround the righteous, is one of the righteous judgments of God. On which account the Apostle Peter saith, "The time is come when judgment must begin at the house of the Lord." For he saith this of the persecutions which the Church suffered, when the bands of the ungodly surrounded them. I suppose, therefore, that by "midnight" we should understand the heavier seasons of tribulation. In which he said, "I arose :" since He did not so afflict him, as to cast him down; but tried him, so that he arose, that is, that through this very tribulation he might advance unto a bolder confession.
Midnight. Under tribulation, (St. Augustine) or to avoid the malice of those who pried into my conduct. I was so delighted with thy law, that I meditated on it both in the day-time, and at night. (Calmet)
This pious custom was observed by St. Paul, (Acts xvi.) as it is still by many religious orders, ver. 164. (Worthington)