Luke
Luke 1:48ESV·traditional attribution

for he has looked on the humble estate of his servant. For behold, from now on all generations will call me blessed;

John Calvin Reformed @genevareformer

48. Because he hath looked She explains the reason why the joy of her heart was founded in God to be, that out of free grace he had looked upon her. By calling herself low she disclaims all merit, and ascribes to the undeserved goodness of God every occasion of boasting.

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 hath regarded the low estate of his handmaiden,.... Meaning, either her outward temporal estate, which was very low and mean: David's family was now very much reduced, it had its seat not at Jerusalem, but at Nazareth, in Galilee: Mary, of that house, was a poor virgin, and Joseph, of the same, to whom she was betrothed, was a poor carpenter; and yet...