Lord, thou hast heard the desire of the humble - Their desire or their prayer that thou wouldst interpose in their behalf in the time of danger, and rescue them. Compare Psalms 6:8-9. The word “humble” here refers to those who were poor, downtrodden, oppressed; and the original reference is, doubtless, to the psalmist himself, and to his friends. He was so certain that God would interpose, he had such assurance that his prayer would he answered, that his mind was perfectly calm.
Thou will prepare their heart - Margin, “or, establish.” The margin seems most accurately to express the meaning of the original word - תכין tākiyn. The idea is, that he would settle or confirm their heart; that is, that he would dispel their fears and allay their apprehensions by the assurances of his favor, and by his gracious interposition. They had been full of apprehension and alarm, but the assurances of the divine favor would establish their hearts and give them peace.
Thou wilt cause thine ear to hear - Another form of expressing assurance of the same thing. The idea is, that he would incline his ear, or make it attentive to the cry of his afflicted people.