| Barnes' Notes on the Bible They remembered not his hand - His gracious interpositions; the manifestations of his power. They forgot that power had been exercised which showed that he was omnipotent - that there was no limit to his ability to aid them. Nor the day when he delivered them from the enemy - The time when he rescued them. The power then manifested was sufficient to defend and deliver them in any new dangers that could befall them. The margin is, from affliction. The Hebrew will admit of either interpretation. The sense is not materially changed.
Gill's Exposition of the Entire BibleThey remembered not his hand,.... Which brought them out of Egypt, and dashed their enemies in pieces, and which had been so often opened to supply their wants in the wilderness; the Targum renders it, the miracles of his hand: nor the day when he delivered them from the enemy; Pharaoh king of Egypt; that very memorable day in which they were delivered out of his hands, that selfsame day which had been fixed, by promise and prophecy many hundreds of years before, in which the hosts of the Lord went out of Egypt, Exodus 12:41, times when as well as places where deliverances and salvation have been wrought should not be forgotten; and forgetfulness of the goodness of God in times past is often the cause and occasion of sinning against him, which, by a remembrance of his kind appearances, might be prevented.
The Treasury of David42 They remembered not his hand, nor the day when he delivered them from the enemy. 43 How he had wrought his signs in Egypt, and his wonders in the field of Zoan: 44 And had turned their rivers into blood; and their floods, that they could not drink. 45 He sent divers sorts of flies among them, which devoured them; and frogs, which destroyed them. 46 He gave also their increase unto the caterpiller, and their labour unto the locust. 47 He destroyed their vines with hail, and their sycomore trees with frost. 48 He gave up their cattle also to the hail, and their flocks to hot thunderbolts. 49 He cast upon them the fierceness of his anger, wrath, and indignation, and trouble, by sending evil angels among them. 50 He made a way to his anger; he spared not their soul from death, but gave their life over to the pestilence; 51 And smote all the firstborn in Egypt; the chief of their strength in the tabernacles of Ham: 52 But made his own people to go forth like sheep, and guided them in the wilderness like a flock. 53 And he led them on safely, so that they feared not: but the sea overwhelmed their enemies. Psalm 78:42 "They remembered not his hand." Yet it must have been difficult to forget it. Such displays of divine power as those which smote Egypt with astonishment, it must have needed some more than usual effort to blot from the tablets of memory. It is probably meant that they practically, rather than actually, forgot. He who forgets the natural returns of gratitude, may justly be charged with not remembering the obligation. "Nor the day when he delivered them from the enemy." The day itself was erased from their calendar, so far as any due result from it or return for it. Strange is the faculty of memory in its oblivions as well as its records. Sin perverts man's powers, makes them forceful only in wrong directions, and practically dead for righteous ends. continued...
Geneva Study BibleThey {a} remembered not his hand, nor the day when he delivered them from the enemy. (a) The forgetfulness of God's benefits is the root of rebellion and all vice.
Wesley's Notes 78:42 Hand - The glorious works of his hand. Enemy - That remarkable day, in which God delivered them from their greatest enemy, Pharaoh.
King James Translators' Notesfrom...: or, from affliction
Matthew Henry's Concise Commentary78:40-55. Let not those that receive mercy from God, be thereby made bold to sin, for the mercies they receive will hasten its punishment; yet let not those who are under Divine rebukes for sin, be discouraged from repentance. The Holy One of Israel will do what is most for his own glory, and what is most for their good. Their forgetting former favours, led them to limit God for the future. God made his own people to go forth like sheep; and guided them in the wilderness, as a shepherd his flock, with all care and tenderness. Thus the true Joshua, even Jesus, brings his church out of the wilderness; but no earthly Canaan, no worldly advantages, should make us forget that the church is in the wilderness while in this world, and that there remaineth a far more glorious rest for the people of God. | 
