When the Lord saw that Leah was hated — That is, loved less than Rachel, in which sense it is required that we hate father and mother, in comparison with Christ, Luke 14:26, then the Lord granted her a child, which was a rebuke to Jacob for making so great a difference between those he was equally related to; a check to Rachel, who, perhaps insulted over her sister upon that account; and a comfort to Leah, that she might not be overwhelmed with the contempt put upon her.
Related Commentaries of Genesis 29:31
Genesis 29:31
31 And when the LORD saw that Leah was hated, he opened her womb: but Rachel was barren.