The Mosaic law did not regulate the offering of prayer, but fully recognized its spontaneous character. In what manner or how far back in Jewish history the sacrificial prayer, mentioned in Lu 1:10, originated no one knows. In the days of Christ it had evidently become an institution. But ages before that, stated hours of prayer were known and religiously observed by all devout Jews. It evidently belonged to the evolutionary process of Jewish worship, in connection with the temple-ritual. Devout Jews, living at Jerusalem, went to the temple to pray (Lu 18:10; Ac 3:1). The pious Jews of the Diaspora opened their windows "toward Jerus" and prayed "toward" the place of God's presence (1Ki 8:48; Da 6:10; Ps 5:7). The regular hours of prayer, as we may infer from Ps 55:17 and Da 6:10, were three in number. The first coincided with the morning sacrifice, at the 3rd hour of the morning, at 9 AM therefore (Ac 2:15). The second was at the 6th hour, or at noon, and may have coincided with the thanksgiving for the chief meal of the day, a religious custom apparently universally observed (Mt 15:36; Ac 27:35). The 3rd hour of prayer coincided with the evening sacrifice, at the ninth hour (Ac 3:1; 10:30). Thus every day, as belonging to God, was religiously subdivided, and regular seasons of prayer were assigned to the devout believer. Its influence on the development of the religious spirit must have been incalculable, and it undoubtedly is, at least in part, the solution of the riddle of the preservation of the Jewish faith in the cruel centuries of its bitter persecution. Mohammedanism borrowed this feature of worship from the Jews and early Christians, and made it one of the chief pillars of its faith.
⇒See also the McClintock and Strong Biblical Cyclopedia.
Henry E. Dosker