2:5 This verse is directly related to v. 4; the paragraph break should come after v. 5 and not before it as in the NIV. - CPNIV
after [according to] -- in a way traceable to. The word “after” here (κατὰ) means in respect to.
hardness -- The Eng. word “sclerosis” (as in arteriosclerosis, a hardening of the arteries) comes from this Greek word. But here the danger is not physical, but spiritual hardness (Ezekiel 36:26; Matthew 19:8; Mark 3:5; Mark 6:52; Mark 8:17; John 12:40; Hebrews 3:8, Hebrews 3:15; Hebrews 4:7). - MSB
The Jews’ sinfulness is described as “stubbornness,” an attitude within Israel that had tried God’s patience from the beginning (Exodus 33:3-5; Exodus 34:9; Deuteronomy 9:13, Deuteronomy 9:27; Ezekiel 3:7). - CPNIV
impenitent heart. A refusal to repent (cf. Romans 2:4).
A soft and repentant heart is needed to avert God’s wrath on the day of wrath, the final judgment. Such repentance would express itself in trust in Jesus Christ for the forgiveness of sins. Paul disagrees with much of the Jewish teaching of his day, according to which the Jews were not storing up wrath but were in good standing with God through their covenant relationship, - ESVSB
treasurest up -- Possibly this word alludes to the “riches” of ver. 4; q. d., “the Divine store of loving-kindness is exchanged by the sinner for the Divine store of holy wrath”. - CBSC
The word for “storing up” is θησαυρίζω (thēsaurizō), which means “to treasure, to heap up, to lay up treasure.” Since we usually associate treasure and laying up treasure with something very valuable and desirable (see Matthew 6:19-20), it is a note of tragic irony that some choose to lay up the “treasure” of God’s wrath. Perhaps by using this word Paul intends to highlight the foolishness of repudiating the riches of God’s kindness (v. 4) and opting instead for the treasure of his wrath. - CPNIV
treasuring up ... wrath -- The idea of storing up wrath is an ironic twist on the usual metaphor of storing up blessings or treasures (compare Genesis 41:49; 1 Timothy 6:19). See note on Romans 1:18. - FSB
for yourself -- Emphatic; more than merely “for thee.” The wrath is pure retribution, the result of sin. The sinner is the cause of his own doom. - CBSC
against the day -- Lit. in the day of wrath; a pregnant phrase; “which will take effect in the day.” On “wrath,” see note on Romans 1:18: “The day:”—i.e. the definite time of the Lord’s Appearing, to raise the dead (John 6:39-40, John 6:44, John 6:54, John 11:24); to judge the world (John 12:48; Acts 17:31); and to receive the saints to final glory (2 Timothy 4:8). In one remarkable passage (1 Corinthians 4:3) the Greek of the word “judgment” (in E. V.) is lit. “day;” and a probable account of this use of the word is the inseparable connexion of thought, in the early church, between the day and the judgment of the Lord. - CBSC
in the day of wrath -- This was called “The Day of the Lord” in the OT (cf. Joel, Amos). This is the concept of Judgment Day, or for believers, Resurrection Day. Mankind will give an account to God for His gift of life (cf. Matthew 25:31-46; Revelation 20:11-15).
Notice that it is the sinners themselves (“you” and “yourself”) that store up wrath. God simply, at some point, allows this stored wrath to become evident and run its full course. - Utley
“The day of God’s wrath” is the general eschatological day of judgment, not the intermediate judgment of a.d. 70, when Jerusalem and the temple were destroyed. This is seen in the fact that in this context the “day of wrath” involves the Gentiles as well as the Jews (Romans 5:8-9, Romans 5:12, Romans 5:16). Revelation 6:17 describes it as “the great day of their wrath.” - CPNIV [However, Revelation 6:17 does refer to the intermediate judgment of AD 70 upon Israel for rejecting Christ. - WG]
day of wrath -- An ot expression synonymous with the Day of Yahweh (e.g., Isaiah 13:6-9; Joel 2:1-11). In the nt, it is also referred to as the Day of Christ (1 Corinthians 1:8; Philippians 1:6)—the second coming of Jesus. On this day of final judgment, God will pour out His wrath against the wicked and deliver His people from evil (1 Thessalonians 5:2 and note). - FSB
revelation of the righteous judgment of God -- The “wrath” is as pure, just, and Divine as the mercy. Its “revelation” will be only the revelation of the absolute equity of “the Judge of all the earth.” This deep righteousness of the Divine anger is its most awful element. - CBSC
And revelation -- On the day when the righteous judgment of God will be revealed, or made known. Here we learn, (1.) That the punishment of the wicked will be just. It will not be a judgment of caprice or tyranny, but a righteous judgment, that is, such a judgment as it will be right to render, or as ought to be rendered, and therefore such as God will render, for he will do right; 2 Thessalonians 1:6. (2.) The punishment of the wicked is future. It is not exhausted in this life. It is treasured up for a future day, and that day is a day of wrath. How contrary to this text are the pretences of those who maintain that all punishment is executed in this life. (3.) How foolish as well as wicked is it to lay up such a treasure for the future; to have the only inheritance in the eternal world, an inheritance of wrath and wo! - BN
This “day of wrath” is also called a “day of revelation” (ἀποκάλυψις, apokalypsis). This word is often associated with the end times and Christ’s second coming (Romans 8:19; 1 Corinthians 1:7; 2 Thessalonians 1:7; 1 Peter 1:7, 1 Peter 1:13; 1 Peter 4:13). Many things will be revealed or totally uncovered on that day, but here Paul specifies that the thing to be revealed is God’s “righteous judgment.” - CPNIV