Luke 1:49

49.And holy is his name This is the second part of the song, in which the holy virgin celebrates in general terms the power, judgments, and mercy of God. This clause must not be viewed as a part of the preceding one, but must be read separately. Mary had extolled the grace of God, which she had experienced in her own person. Hence she takes occasion to exclaim, that holy is his name, and his mercy endures throughout all generations The name of God is called holy, because it is entitled to the highest reverence; and whenever the name of God is mentioned, it ought immediately to remind us of his adorable majesty.

The next clause, which celebrates the perpetuity of the Divine mercy, is taken from that solemn form of covenant,

“I will establish my covenant between me and thee, and thy seed after thee, in their generations, for an everlasting covenant,”
(Genesis 17:7)

and again,

“who keepeth covenant and mercy with them that love him and keep his commandments to a thousand generations,” (Deuteronomy 7:9.)

By these words, he not only declares, that he will always be like himself, but expresses the favor which he continues to manifest towards his own people after their death, loving their children, and their children’s children, and all their posterity. Thus he followed the posterity of Abraham with uninterrupted kindness; for, having once received their father Abraham into favor, he had made with him “an everlasting covenant.”

But as not all who are descended from Abraham according to the flesh are the true children of Abraham, Mary confines the accomplishment of the promise to the true worshippers of God, to them that fear him: as David also does:

“The mercy of the Lord is from everlasting to everlasting upon them that fear him, and his righteousness unto children’s children; to such as keep his covenant, and to those that remember his commandments to do them,”
(Psalms 103:17.)

While God promises that he will be merciful to the children of the saints through all generations, this gives no support to the vain confidence of hypocrites: for falsely and groundlessly do they boast of God as their Father, who are the spurious children of the saints, and have departed from their faith and godliness. (54) This exception sets aside the falsehood and arrogance of those who, while they are destitute of faith, are puffed up with false pretenses to the favor of God. A universal covenant of salvation had been made by God with the posterity of Abraham; but, as stones moistened by the rain do not become soft, so the promised righteousness and salvation are prevented from reaching unbelievers through their own hardness of heart. Meanwhile, to maintain the truth and firmness of his, promise, God has preserved “a seed,” (Romans 9:29.)

Under the fear of the Lord is included the whole of godliness and religion, and this cannot exist without faith. But here an objection may be urged. What avails it that God is called merciful, if no man finds him to be so unless he deserves his favor? For, if the mercy of God is upon them that fear him, godliness and a good conscience procure his grace to men, and in this way men go before his grace by their own merits. I reply, this is a part of his mercy, that he bestows on the children of the godly fear and reverence for his majesty. This does not point out the commencement of his grace, as if God were idly looking down from heaven, to see who are worthy of it. All that is intended is, to shake off the perverse confidence of hypocrites, that they may not imagine God to be bound to them, because they are the children of saints according to the flesh: the divine covenant having another and very different object, that God may have always a people in the world, by whom he is sincerely worshipped.