How can spouses and children be an enemy or a trial, as mentioned in the Holy Qur'an?

Allah warned His believing servants that some of their spouses and children might be enemies to them, and that wealth and children are a trial, as He Subhanahu says: "O you who have believed, indeed, among your wives and your children are enemies to you, so beware of them. But if you pardon and overlook and forgive – then indeed, Allah is Forgiving and Merciful. Your wealth and your children are only a trial, and Allah has with Him a great reward." [At-Taghabun: 14-15]. This enmity means that they might distract a person from righteous deeds, or lead him to sever kinship ties, or fall into disobedience. The noble verses and prophetic hadiths have shown that children and wealth can push a father to cowardice, stinginess, and ignorance, and divert him from obedience to Allah and His remembrance. Therefore, a Muslim should beware of this in order to be safe.