It appears, from the Scriptures, that the Lord allows a certain amount of time for people to repent of their sins before His judgment falls upon them. This amount of time is known only to the Lord.
For instance, we learn in Genesis 15:16, where the Lord tells Abram (Abraham) about his descendants coming into the land of promise: "But in the fourth generation they shall come hither again: for the iniquity of the Amorites is not yet full." After the iniquity of the Amorites became full, they were judged severely by the Lord.
When the Lord made an appearance to Abraham with two of His angels, He was on the verge of investigating the sins of the cities of Sodom and Gomorrah which had been mounting unto heaven for a long time. Genesis 18:17- 22 tells us: "And the LORD said, Shall I hide from Abraham that thing which I do;Seeing that Abraham shall surely become a great and mighty nation, and all the nations of the earth shall be blessed in him? For I know him, that he will command his children and his household after him, and they shall keep the way of the LORD, to do justice and judgment; that the LORD may bring upon Abraham that which he hath spoken of him. And the LORD said, Because the cry of Sodom and Gomorrah is great, and because their sin is very grievous;I will go down now, and see whether they have done altogether according to the cry of it, which is come unto me; and if not, I will know. And the men turned their faces from thence, and went toward Sodom: but Abraham stood yet before the LORD."
We know that before the Lord sent the great Flood of Noah's day to destroy all flesh upon the face of the earth, that He gave the wicked people about a hundred years to repent while Noah was constructing the ark and preaching to these people (see Genesis 6:5-7; II Peter 2:5). In the book of Revelation a wicked woman named Jezebel is given a certain amount of time to repent of her sins. Revelation 2:20-23 tells us about events in the Church of Thyatira: "Notwithstanding I have a few things against thee, because thou sufferest that woman Jezebel, which calleth herself a prophetess, to teach and to seduce my servants to commit fornication, and to eat things sacrificed unto idols. And I gave her space to repent of her fornication; and she repented not. Behold, I will cast her into a bed, and them that commit adultery with her into great tribulation, except they repent of their deeds. And I will kill her children with death; and all the churches shall know that I am he which searcheth the reins and hearts: and I will give unto every one of you according to your works."
In every one of these situations the chance to repent was not used by the people involved: the Amorites did not repent of their sins, the folks of Sodom and Gomorrah did not repent, the people before the Flood did not repent, and Jezebel from the Church of Thyatira did not repent. And yet, the Lord was merciful, and faithful, in giving them the space of His grace. Even when the Lord sends upon the earth the fullness of His wrath during the seven last plages, people still won't repent.
We see this from Revelation 9:20-21: "And the rest of the men which were not killed by these plagues yet repented not of the works of their hands, that they should not worship devils, and idols of gold, and silver, and brass, and stone, and of wood: which neither can see, nor hear, nor walk: Neither repented they of their murders, nor of their sorceries, nor of their fornication, nor of their thefts." Let us not be like these hard hearted people who throw away God's mercy and grace until all that is left to them is His judgment.
May we ever use the space of God's grace as a time to look within our hearts to see if we need to repent from our sins and to let the blood of Christ cleanse us. May we be like the Psalmist who wrote: "Search me, O God, and know my heart: try me, and know my thoughts: And see if there be any wicked way in me, and lead me in the way everlasting" (Psalm 139:23-24).