One impediment to repentance

"Men flatter themselves in sin and think that God, having spared them all this while, never intends to punish. Because the assizes are put off, therefore, surely there will be no assizes. 'He hath said in his heart, God hath forgotten: he hideth his face, he will never see it' (Ps. 10.11). The Lord indeed is longsuffering towards sinners and would by his patience bribe them to repentance, but here is their wretchedness; because he forbears to punish they forbear to repent. Know, that the lease of patience will soon run out. There is a time when God will say, 'My Spirit shall not always strive with man' (Gen. 6.3). A creditor may forbear his debtor, but forbearance does not excuse the payment. God takes notice how long the glass of his patience has been running: 'I gave her space to repent; and she repented not' (Rev. 2.21). Jezebel added impenitence to her incontinency, and what followed? 'Behold, I will cast her into a bed' (Rev. 2.22), not a bed of pleasure, but a bed of languishing where she will consume away in her iniquity. The longer God's arrow is drawing, the deeper it will wound. Sins against patience will make a man's hell so much the hotter."

From The Doctrine of Repentance, by Thomas Watson