David
Psalm 42:8ESV·traditional attribution

By day the LORD commands his steadfast love, and at night his song is with me, a prayer to the God of my life.

John Calvin Reformed @genevareformer

PSALM 42 In the first place, David shows that when he was forced to flee by reason of the cruelty of Saul, and was living in a state of exile, what most of all grieved him was, that he was deprived of the opportunity of access to the sanctuary; for he preferred the service of God to every earthly advantage.

Commenting on Psalm 42:1-11

C.H. Spurgeon Reformed Baptist @princeofpreachers

Yet the Lord will command his lovingkindness in the daytime. Come what may there shall be "a certain secret something" to sweeten all. Lovingkindness is a noble life belt in a rough sea. The day may darken into a strange and untimely midnight, but the love of God ordained of old to be the portion of the elect, shall be by sovereign decree meted out to them.

Matthew Henry Presbyterian @wholebiblehenry

Complaints and comforts here, as before, take their turn, like day and night in the course of nature. I. He complains of the dejections of his spirit, but comforts himself with the thoughts of God, Psa 42:6. 1. In his troubles. His soul was dejected, and he goes to God and tells him so: O my God! my soul is cast down within me.

Commenting on Psalm 42:6-11