Gregory the Great — on 1Sam 3:21 (Commentary on 1 Kings, Book 3, Chapter 1)

“29. For Shiloh is interpreted as "sent." And because He sends into the ministry of preaching even to the end of the world, the Lord appears in Shiloh, because He shows Himself more clearly to those through whom He opens the glory of His light to others. Moreover, it is well said, "He continued to appear," because those upon whom the brightness of the divine light is poured are unceasingly chosen. Whence he also adds the reason why he affirms the vision was heard, saying: (Verse 21.) Because the Lord had revealed Himself to Samuel. 30. For this reason he adds "so that he might appear," because the Lord who had been revealed reveals himself again and again, and by no means withdraws the gift of his manifestation from holy Church, which he has not ceased to bestow upon her from her beginning. But although it is stated that he was revealed to Samuel, it is not reported how many times he continued to appear, because indeed holy Church is led all the way to the end of the world, over which preachers preside, who preach the lofty joys of eternity among those below, inasmuch as they see the highest things they preach in the lofty manifestation of God. Which appearance indeed is declared to have been made according to the word of the Lord. But what is the word of the Lord, if not the promise of the Redeemer? He continued therefore to appear according to the word of the Lord, because he does not cease to display the truth of his promise. For the word of the Lord in the continuation of his appearing is: "Behold, I am with you all days, even to the consummation of the age" (Matt. 28:20). There follows: (Verse 21.) And the word of Samuel came to all Israel. 31. For the word is known to come when the promise of our preachers is fulfilled. For the promise of the word is joy that will endure without end. Therefore the word of Samuel came to all Israel, because the entire multitude of the holy Church arrives at the joy of eternal blessedness, and what is now promised in the faith of the word by its holy preachers is bestowed upon it in truth in the heavenly kingdoms. For the word of the teachers in the promise of the faithful is: Everyone who believes in him shall not perish, but shall have eternal life (John 3:15). Or certainly the word of the teachers in the promise of gifts is: What eye has not seen, nor ear heard, nor has it ascended into the heart of man, what God has prepared for those who love him (Isa. 64:4; 1 Cor. 2:9). And so the word of Samuel came to all Israel, because whoever believes the holy preachers both urging a devout manner of life in the present and promising eternal joys to the just, has passed by dying in the flesh to those eternal joys which he had awaited by living piously. Whence he in whose faith he had promised also affirms, saying: Amen I say to you, heaven and earth shall pass away, but my words shall not pass away (Mark 13:31). Or certainly the word of Samuel has now come to all Israel, because through the effect of divine punishment the general rejection of the Jews is recognized as fulfilled.”