Theophylact of Ohrid

In a figurative sense, this can be understood as follows: the word of Teaching, sowing good seeds in the soul of a believing person, has the significance of a husband to the soul that receives it. And it leaves its father, that is, lofty thought, and its mother, that is, embellished speech, and cleaves to its wife, that is, to the benefit of the soul, adapting itself to it and often preferring humble thoughts and simple speech. …

Commentary on Mark ↗

Bede

For this cause shall a man leave his father and mother, and shall cleave to his wife. Similarly, He said, Cleave to his wife, not to wives.

On the Gospel of Mark ↗