Luke
Luke 1:49ESV·traditional attribution

for he who is mighty has done great things for me, and holy is his name.

John Calvin Reformed @genevareformer

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.

Matthew Henry Presbyterian @wholebiblehenry

We have here an interview between the two happy mothers, Elisabeth and Mary: the angel, by intimating to Mary the favour bestowed on her cousin Elisabeth (Luk 1:36), gave occasion for it; and sometimes it may prove a better piece of service that we think to bring good people together, to compare notes. Here is, I. The visit which Mary made to Elisabeth.

Commenting on Luke 1:39-56

John Gill Reformed Baptist @doctorgill

For he that is mighty hath done to me great things,.... With respect to the incarnation of Christ, a new, a great, and unheard of thing; in causing her, though a virgin, to conceive; and also to bear such a Son, who should be called Jesus, a Saviour, Immanuel, God with us; and who was no other than the mighty God, the everlasting Father, and...