1 Samuel 16:1

The Jews had before been directed to compose a sacred oil, with which those who were called to the priesthood or to the kingdom might be anointed. And as now the robe of purple is a sign of the assumption of royal dignity among the Romans, so with them the anointing with the holy oil conferred the title and power of king. But since the ancient Greeks used the word chriesthai to express the art of anointing, which they now express by anleiphesthai, as the verse of Homer shows, "But the attendants washed, and anointed them with oil"; on this account we call him Christ, that is, the Anointed, who in Hebrew is called the Messiah.

1. For when it is said to him: "How long will you mourn?" it is shown that he was mourning persistently. Great, therefore, is the affection of the saints, even when they outwardly bring forth the severity of punishment. For on the outside they rage, but inwardly they melt with love. In the manner of mothers they strike their little ones, yet they groan with the affection of the little ones whom they chastise. But what does it mean that the Lord says: "How long will you mourn for Saul?" Can a mother see her son dying and not weep at all through the rending of her heart? She who dies endures the dead without grief, but is weakened. What does it mean that He says: "How long will you mourn for Saul?" Unless it is because the lost are not to be mourned excessively? For often a teacher is vehemently afflicted over the perdition of his subject, but is consoled by regard for the supreme justice. What, therefore, does this saying of God to the prophet mean, except to relieve the preacher's mind from affliction through inward consolation? And because, when prelates have fallen, the elect are substituted through divine mercy, the Lord adds, saying: (Verse 1.) "Fill your horn with oil, and come: I will send you to Jesse the Bethlehemite. For I have provided among his sons a king for myself." 2. For as if consoling one who mourns, he says: Why is the casting off of one person lamented, when a better one is substituted? Hence Saul is shown as not foreseen, but David as foreseen. How great, therefore, and of what quality he was, let it be weighed with prompt consideration—he who is determined by the judgment and choice of Almighty God. […]

22. Now indeed, according to our plan, the book ought to be brought to a close at its end; but it returns to memory that we referred the beginnings of the volume to the conversation of the Redeemer. And since through John our same Redeemer is declared to be the beginning and the end, the book is most fittingly closed if it is completed in the narration of our Redeemer (Rev. 1:8). David, therefore, meaning "strong of hand," represents the Redeemer of the human race Himself, who prevailed over the ancient enemy and carried away the elect from his power. He is called the son of Jesse the Bethlehemite, because He willed to be born from that people whom He filled, as it were with bread, with the knowledge of the Holy Scriptures. For Judea was the "house of bread," which possessed the solid food of the Scriptures in spiritual understanding, as if from bread. But what does Samuel signify, except, as we have already often said, the order of the new preachers? And what does David represent, except the Redeemer? Samuel is therefore sent to anoint him. For to anoint him is to preach his incomparable sanctification to those who are ignorant of it. For he is, as it were, anointed when the fragrance of his renown is opened to those who do not know him. For he was anointing Him who said: "Because in him all the fullness of the Godhead dwells bodily" (Col. 2:9). But why do we take only the new preachers as pertaining to his anointing, when we see that the old ones also anointed him so reverently? For what smells better and sweeter than what the prophet Isaiah poured out upon him, saying: "The Spirit of the Lord shall rest upon him, the spirit of wisdom and understanding, the spirit of counsel and fortitude, the spirit of knowledge and piety; and the spirit of the fear of the Lord shall fill him" (Isa. 11:2)? […]

Fill your horn with oil, and come, etc. Leaving behind, he says, the care of the carnal kingdom, embrace rather that dominion, which by the light of the Holy Spirit is ascertained to be most rich, to be hoped for and loved. This not coming …

I have provided - This phrase is very emphatical, and implies the difference between this and the former king. Saul was a king of the people's providing, he was the product of their sinful desires: but this is a king of my own providing, to fulfil all my will, and to serve my glory.