Indifference to sin is the transition to hardness of heart, but it is not yet hardness. The indifferent man can still be awakened. Only a special power of God can transform the hardened man. People reach hardness through repeated awakenings from indifference and amendment of life, and then through falling back into it again by repeated sins. Divine truths awaken. When all these truths have exhausted their power to awaken the sinner, by what will you awaken him? His heart has become like a stone that no instrument can cut. "When goodness does not soften a man and fear does not bend him, what can be harder-hearted?" (Saint Chrysostom). After such hardening comes hostility toward God and all that is divine. After this comes despair, the final ruin. Hardness, or hardness of heart, is explained by an unrepentant heart. The sinner has reached impenitence and lies calmly in sins, no longer suspecting any danger to himself. Meanwhile, what is he doing? He is storing up wrath for himself. Wrath is God's righteous recompense for every evil deed, word, and thought. It is called wrath "according to the sinner's feeling" (Ambrosiaster), who receives the Judge's determination, not according to the Judge's state. "See what fitting expressions the Apostle uses. He says: 'You are storing up wrath for yourself,' showing that the cause of wrath is not the Judge, but the defendant. You store it up for yourself, not God. He has done everything necessary. He endowed you with the ability to distinguish good and evil. He showed longsuffering, called you to repentance, and threatened the fearful day, moving you by every means to repent. But if you are unbending, then you store up wrath for yourself on the day of wrath" (Saint Chrysostom). You are storing up, θησαυρίζεις, means you are treasuring up. As someone, laying ruble upon ruble into a chest, finally gathers a great treasure, so everyone living on earth gathers treasure in heaven by adding deed to deed. It will serve him either as eternal provision or as eternal deprivation. "The Apostle spoke beautifully: 'You are storing up for yourself,' showing that none of our words or deeds will be given over to oblivion. On the contrary, lovers of virtue store up goods for themselves, and the workers of wickedness do the same, storing up, though not goods" (Blessed Theodoret). Now this treasure is not visible, but it will surely be revealed on the day of God's righteous judgment. What will be revealed for each person can be foreseen even now. Yet for very many these revelations will be unexpected, as the Lord indicates in His depiction of the judgment. For many will say: when did we see You? Thus all are treasuring up. The sinner too is treasuring up. But what? Wrath on the day of wrath and of the revelation of the righteous judgment of God. What is wrath? Evil deeds for which strict punishment will follow, reflected in the sinner's heart as God's wrath. What is the day of wrath? The following words explain this: and of the revelation of the righteous judgment of God. On that day God's righteous judgment will be carried out. But sinners, having lost every right feeling, will conceive this righteousness as wrath. Therefore for them it is a day of wrath. Even there God's mercy will seek how to justify the sinner. It will hand him over to God's righteousness only after nothing can be applied to his justification. Yet despite this, for sinners it will still be a day of wrath, which will penetrate their whole being. The Apostle sets down two expressions. One says what that day will be for sinners, and the other what it is in itself. For sinners it is the day of wrath. In itself it is the day of the righteous judgment of God. "Lest, hearing of wrath, you consider it an action of passion, the Apostle adds: of the righteous judgment of God" (Saint Chrysostom). The word revelation means manifestation. The day of revelation is the day when the Judge will appear and God's judgment will be disclosed. Together with this one may infer that this day will be revealed suddenly. As lightning shines unexpectedly from one end of heaven to the other, so God's judgment will be revealed. One may also dwell on this thought, that then everything will be disclosed, and nothing can be hidden. "Then there will be a revelation of everything, and recompense will accord with what is revealed. Consequently the judgment will be righteous. Here righteousness does not always prevail, because deeds are hidden. But there, after the revelation, righteous judgment follows" (Blessed Theophylact).