Albert Barnes on Acts 12:5

But prayer was made. The church was apprized of his imprisonment and danger; and had no resource but to apply to God by prayer. In scenes of danger there is no other refuge; and the result shows that, even in most discouraging circumstances, God can hear prayer. Nothing scarcely could appear more hopeless than the idea of rescuing Peter out of the hands of Herod, and out of the prison, and out of the custody of sixteen men, by prayer. But the prayer of faith was prevalent with God.

Without ceasing. Intense, steady, ardent prayer. The word here used, εκτενης, is found in but one other place in the New Testament. 1Pet 4:8: "Have fervent charity among yourselves." The word has rather the idea that their prayer was earnest and fervent, than that it was constant.

Of the church. By the church.

(1) "prayer" "instant and earnest prayer was made" 2Cor 1:11, Eph 6:18,19, 1Thes 5:17, Jas 5:16 (*) "without ceasing" "earnestly"