At midnight I will rise to give thanks unto thee because of thy righteous judgments.

Jamieson-Fausset-Brown Bible Commentary

62. At midnight-Hengstenberg supposes a reference to the time when the Lord went forth to slay the Egyptian first-born (Ex 11:4; 12:29; compare Job 34:20). But it rather refers to the Psalmist's own praises and prayers in the night time. Compare Paul and Silas (Ac 16:25; compare Ps 63:6).

Matthew Henry's Concise Commentary

119:57-64 True believers take the Lord for the portion of their inheritance, and nothing less will satisfy them. The psalmist prayed with his whole heart, knowing how to value the blessing he prayed for: he desired the mercy promised, and depended on the promise for it. He turned from by-paths, and returned to God's testimonies. He delayed not. It behoves sinners to hasten to escape; and the believer will be equally in haste to glorify God. No care or grief should take away God's word out of our minds, or hinder the comfort it bestows. There is no situation on earth in which a believer has not cause to be thankful. Let us feel ashamed that others are more willing to keep from sleep to spend the time in sinful pleasures, than we are to praise God. And we should be more earnest in prayer, that our hearts may be filled with his mercy, grace, and peace.