When God judges the heart, He does so because sinners love the kind of dualism that gives their sin a place to hide. “You are near in their mouth but far from their mind” (Jer. 12:2b, NKJV).
But when someone is unconverted, that condition is not a mystic invisibility, seen only by God. No, it comes out in his life, in his ways. This is why Paul says that the works of the flesh are manifest. “I, the Lord, search the heart, I test the mind, even to give every man according to his ways, according to the fruit of his doings” (Jer. 17:10, NKJV).
In our sin, we want to keep inside and outside distinct, so that we can “manage” them, so we can run our simplistic little inventory systems. But in the judgment, the Lord treats the whole thing as an integrated unit. The sinner wants to plead that while he may have sin in his heart, at least he says the Creed and tithes (sometimes). Christ must be here somewhere. The Lord sees the sin in the heart, and the Creed, and the money, and the constant anger toward family, and the porn, and the envious snark, and no Christ anywhere.
And when Christ is not present, blessing, His absence is manifest.