Albert Barnes Commentary Psalms 59:15

"They shall wander up and down for food, And tarry all night if they be not satisfied." — Psalms 59:15 (ASV)

Let them wander up and down for meat - Let them be like dogs that wander about for food and find none. The idea is that they would not find him and would then be like dogs that had sought food in vain.

And grudge if they be not satisfied - The margin says, "If they be not satisfied, then they will stay all night." The marginal reading is most in accordance with the Hebrew. The sentence is obscure, but the idea seems to be that they would not be satisfied—that is, they would not obtain what they had sought. Like hungry and disappointed dogs, they would be compelled to pass the night in this miserable and wretched condition. The word that our translators have rendered as “grudge”—from לוּן lûn—properly means to pass the night. It can also mean to abide, to remain, or to dwell. In Hiphil, it means to show oneself obstinate and stubborn, from the idea of remaining or persisting in a bad cause. Consequently, the word sometimes means to complain (Numbers 14:29; Exodus 17:3).

It does not, however, have the meaning of grudging, though it might mean here to murmur or complain because they were disappointed. But the most natural meaning is what the word properly conveys—that of passing the night, referring to their wandering about, disappointed in their objective, yet still hoping they might possibly obtain it. The anticipated feeling in the psalmist’s mind is what he would experience from the awareness of his own safety and the pleasure of knowing that they must sooner or later discover that their victim had escaped.