Commentators explain a paradox in this verse: the heart is 'weak' while the actions are 'strong' or 'imperious.' The weakness isn't feebleness, but spiritual instability and an inability to resist temptation. This moral weakness, however, leads to bold, audacious, and shameless sin, like a harlot who has cast off all restraint. Scholars like John Calvin note that these two traits—a fickle heart and brazen rebellion—are often found together in those who turn from God.