St. Frances de Sales shows how the visitation of Mary to Elizabeth illustrates the truth that humility and charity go together.
Our Lady was not satisfied with having humbled herself before the divine Majesty, for she well knew that humility and charity are not in their perfection until they are transmitted to their neighbor. From the love of God proceeds love of neighbor, and the great apostle says that the greatness of your love for your brothers will be directly proportioned to the greatness of your love for God (see Rom 13:8; Gal 5:14; Eph 5:1–2). St. John teaches us this when he writes: “How can it be that you love God, whom you do not see, if you do not love your neighbor, whom you do see” (1 Jn 4:20)?
If we then wish to prove that we do indeed love God, and if we wish others to believe us when we assure them of this, we must love our brothers well, serve them, and assist them in their necessities. Now the holy Virgin, knowing this truth, set out promptly, says the evangelist, proceeding in haste into the hill country of Judah (see Lk 1:30), into the town of Hebron or, as others say, Jerusalem (it matters little), to serve her cousin Elizabeth in her advanced age and pregnancy.
In this she manifested great humility and charity; for as soon as she saw herself Mother of God, she humbled herself to the point of immediately setting out on the road to go help and assist that good woman. —St. Francis de Sales, Sermon for the Feast of the Visitation
Thigpen, Paul. A Year with Mary: Daily Meditations on the Mother of God (p. 425). Saint Benedict Press. Kindle Edition.