The verse pinpoints a specific action: 'married the daughter of a strange god.' What's the big deal about who someone marries?
This phrase, 'daughter of a strange god,' isn't just about a woman from a different nation. It signifies marrying someone whose heart and allegiance belong to an idol, to a deity other than the LORD.
In the ancient world, marriage was a profound covenant that shaped family, worship, and identity. Marrying an idolater meant bringing the worship of foreign gods into the covenant community of Israel. It was a direct threat to their spiritual purity and their exclusive devotion to Yahweh.
As the commentators note, worshippers were often seen as 'children' of their gods. So, marrying a 'daughter of a strange god' was akin to becoming a relative of that idol, drawing the worshipper and their descendants into the orbit of paganism. This action directly profaned the 'holiness' of the LORD because it diluted the unique covenant relationship God desired with His people.