Romans 2:5

‘But after your hardness and impenitent heart you treasure up for yourself wrath in the day of wrath and revelation of the righteous judgment of God.

But rather than repenting their hearts are hard and impenitent. They ignore God's pleadings and carry on in their old ways. As a result they are treasuring up for themselves wrath, a wrath which will be applied to them in the day of wrath and righteous judgment of God when God will render to every man according to his works. There is something very sad about the thought of a man hoarding up God's wrath, like a squirrel hoards up nuts, without realising it. Every day he adds to his sins. And every day the burden of responsibility grows larger, and God's antipathy towards him increases. Note how the hard and impenitent heart is in total contrast to the goodness, compassion and longsuffering of the God Whom they ignore. It is man who is hard, not God.

But he needs to remember that a day is coming on which every man will have to give account, a day of wrath and of the righteous judgment of God (1 Thessalonians 1:8; Acts 17:31; Hebrews 9:27). Then man will be faced up with his sins. Then the wrath that has been hoarded up will be applied. Then God's righteous judgment will be exacted, and He will render to each according to their works, according to how they have behaved, according to what they have done. What has been done in the dark will be brought to the light, and what has been done in secret will be made known to all. And what is worse, it will come before the attention of a God Who is holy and righteous.

Note the idea of a building up of wrath. Everything that we do is to be seen as helping to build up that wrath, for by our actions we are increasing God's antipathy against our increasing sinfulness. Unless we repent we are building up within ourselves a mountain of sin and guilt.

‘The day of wrath --.' The phrase is based on Psalms 110:5 (see also Zephaniah 1:14; Revelation 6:17). Jesus applied this Psalm to Himself when demonstrating that He was greater than David (Mark 12:36; Psalms 110:1), and the Psalm is about the triumph of the Davidic king, who is also priest after the order of Melchizedek (compare Hebrews 7), who will judge among the nations on the day of His wrath. So there is in this a clear pointing to Jesus.