Psalms 99:6
Moses and Aaron among his priests, and Samuel among them that call upon his name; they called upon the LORD, and he answered them. Moses and Aaron among his priests, and Samuel among them that call upon his name; they called upon the LORD, and he answered them.
Psalm 99:6 stands within Psalms 95 to 106, which recount in song God's wonderful history and providences that Israel was ever to keep before them. It names Moses and Aaron among His priests and Samuel among those who call upon His name, declaring that they called upon the Lord and He answered them, showing that God hears and answers those who pray to Him.
Samuel is presented as one of those who called on the Lord and was answered, whose intercession helped carry Israel through the troubled transition from the judges to the kings. Without his prayers Israel would have faced defeat, and he regarded ceasing to pray for the people as a sin. Moses, Aaron, and Samuel are shown among those who called on the Lord and were answered, which is applied to show that they kept God's Sabbath ordinance.
Moses is shown among those who served as priests and called on the Lord, identifying him as the first priest under the old covenant. Because he was its first priest, he represents the old covenant. In that priestly office, and as the prophet like unto whom Christ came, Moses was a type of Christ, faithful in his house as a servant for a testimony of things to be spoken after while Christ is Son over His own house, so that the house of Moses, the house of Israel, bears the same relation to the house of Christ, the household of faith who hold fast confidence and hope, as Moses bears to Christ, that of type to antitype.