Moses and Aaron among his priests - Among the ministers of religion; or, as officiating in the service of God. Let them come as representatives of their order - as representing those who conduct the public worship of God, and join in his praise. The idea is, that all mankind should join in his praise, and those mentioned here as among the most eminent of those who were engaged in directing the public worship of God. Moses could be called a “priest” only in the most general sense of the term, as having been employed in directing and arranging for public worship, and as being of the original tribe of Levi, from whom the whole sacerdotal order sprang.
And Samuel among them that call upon his name - Among those who are true worshippers, in distinction from the priests who were specially appointed to the public service of God. The idea is, that praise should be offered by “all” classes: by priests and by people. As Moses and Aaron were among the most eminent of the former class, so Samuel was among the most distinguished of those who were not of the priestly order. These were “representative men;” and the meaning is, that all who were of their order or rank - priests and people - should unite in the worship of God.
They called upon the Lord - They did call upon the Lord; they worshipped Yahweh. They gave the influence of their names and of their position to his public service. They thus showed their sense of the propriety of praising God; they gave the countenance of their example to public worship and praise; and the benefits which they received in answer to prayer showed the propriety and advantage of thus publicly acknowledging God.
And he answered them - They did not call upon him in vain. He heard their prayers. He bestowed blessings on them in connection with their worship. It was not a useless thing to praise and worship him. The worship of God is thus commended to us not merely from the propriety of the act itself, but from its advantages. It is unnecessary to refer to particular instances in the history of these people when their prayers were answered. Their lives were full of such instances - as the lives of all who truly call upon God are now. If a man who prays could “see” all that comes to him every day in answer to prayer - all the things bestowed which he had “desired” in prayer, and which would not have been conferred on him if he had not prayed, there would no longer be any doubt on the question whether God answers prayer.