What is man, that he should be clean? and he which is born of a woman, that he should be righteous? Behold, he putteth no trust in his saints; yea, the heavens are not clean in his sight. How much more abominable and filthy is man, which drinketh iniquity like water? (Job 15:14-16)
In Ephesians 2:1, Paul wrote, “and you hath he quickened, who were dead in trespasses and sins”.So, Job said that we are filthy and Paul said that we are dead. I John 3:8 tells us that we belong to the devil:“He that committeth sin is of the devil”. We can see from this that man is in desperate need of help. He is filthy, dead, and has the devil. To be spiritually dead refers to separation from God; it does not mean to be physically dead. At this point, there is no fellowship between man and God. Therefore, we need life; and the doctrine of regeneration explains how we obtain life. You are spiritually dead until you become a believer in Jesus Christ, and there is no relationship between you and God. When you speak to certain people about the Gospel of Jesus Christ, you will find that they do not respond, for they are dead. They cannot respond to your words in a spiritual realm any more than a body in a grave can respond to words spoken in the natural realm.
For our transgressions are multiplied before thee, and our sins testify against us: for our transgressions are with us; and as for our iniquities, we know them. (Isaiah 59:12)
Holiness is a characteristic that God alone possesses. To be holy is to be set apart because when we say that God is holy, we mean that He is entirely different from men. He is set apart from us. He cannot enter fellowship with us because of our sin—there is a separation. The nature of God’s holiness means that it is necessary for a change to take place within us if we are to enter His presence. We do not need to be altered, influenced, re-invigorated, or reformed; neither do we need a good case of religion. We need to have a work of God within us. He only receives unto Himself those who have perfect righteousness or those who possess divine life. Another reason for regeneration is the character of Heaven, itself.
And there shall in no wise enter into it any thing that defileth, neither whatsoever worketh abomination, or maketh a lie: but they which are written in the Lamb\’s book of life. (Revelation 21:27)
Heaven is a place where absolute purity prevails. New Jerusalem is a holy city, a glorified city, and only those who are holy and pure shall enter that city.