A.T. Robertson Commentary Romans 2:5

"but after thy hardness and impenitent heart treasurest up for thyself wrath in the day of wrath and revelation of the righteous judgment of God;" — Romans 2:5 (ASV)

After thy hardness (κατα την σκληροτητα σου). "According to thy hardness (old word from σκληρος, hard, stiff, only here in N.T.) will God's judgment be."

And impenitent heart (κα αμετανοητον καρδιαν). See μετανοιαν just before. "Thy unreconstructed heart," "with no change in the attitude of thy heart."

Treasurest up for thyself (θησαυριζεις σεαυτω). See for θησαυριζω on Mt 6:19f.; Luke 12:21; 2 Corinthians 12:14. Dative case σεαυτω (for thyself) with a touch of irony (Vincent).

Wrath (οργην). For such a Jew as already stated for the Gentile (1:18). There is a revelation (αποκαλυψεως) of God's wrath for both in the day of wrath and righteous judgment (δικαιοκρισιας, a late compound word, in LXX, two examples in the Oxyrhynchus papyri, only here in N.T.). See 2 Thessalonians 1:5 for δικαιας κρισεως. Paul looks to the judgment day as certain (cf. 2 Corinthians 5:10–12), the day of the Lord (2 Corinthians 1:14).