50 Let there be in him faith and ripeness of character, not one without the other, but let both meet together in one with good works and deeds. For which reason the Apostle Paul wishes that we should be imitators of them, who, as he says, “by faith and patience” possess the promises made to Abraham, who by patience was found worthy to receive and to possess the grace of the blessing promised to him. David the prophet warns us that we should be imitators of holy Aaron, and has set him among the Saints of God to be imitated by us, saying: “Moses and Aaron among his priests, and Samuel among those that call upon His Name.”
Source: Letters (New Advent)