Wherever in scripture punishment for human sin is quantified, it is typically specified at double the offence; a principle applied quite literally in the Law of Moses for all manner of theft (e.g. Ex22:4,7,9). Likewise in the Prophets, God’s rebellious people are said to pay double for their sins (Is40:2, Jer16:18) as at the universal level in final judgement do the wicked (Jer17:18, Rev18:6). “Double” need not be taken literally in the latter cases but it is indicating that punishment in God’s eyes is proportional and finite, for nX≠∞ (where n is the multiple and X is the offence). Even so, thinking back through human history and applying such a principle it is no surprise that Jesus said of a few: “it had been better for them if they had never been born”, especially those who through megalomania or merciless psychopathy have brought untold misery to numerous lives, for they will pay a heavy price. They will not suffer because of any deficiency or “limit” to Christ’s atonement; nor, it should be noted, is final punishment presented in the gospels in terms of offences against God but against humanity (Mt25:41-46). Why? – because God makes full allowance for ignorance; man’s knowledge of the Divine Glory is at the very best incomplete, especially for the majority who have not received a faithful account of the Gospel. But there is less excuse with regard to dealings with our fellow man, for the requirement to be caring and compassionate is intuitive (Mt25 again), being discerned through the faculty of conscience, by which (to the astonishment of many) Paul asserts that many without the Law do, however feebly, the one thing required to fulfil its central purpose (Rom2:14,15; Rom13:8; Gal5:14).
One can take it from Christ Himself that human sin will be punished in accordance with the criteria stipulated by the Judge who is Himself a Man (Jn5:22), applying standards that will be seen by all to be fair and just (Mt6:14; 7:2). Of course with our God there is forgiveness a plenty, but retributive post-mortem punishment and exclusion from the blessings of God’s future Kingdom (i.e. Hell) for some is a biblically inescapable reality, albeit applying the principles established above . Such punishment and exclusion will be seen to be right and just and indeed necessary, once a new heaven and earth is established under Christ with His saints, in which righteousness shall dwell (2Pet3:13).
Note 1: References in the New Testament to punishment being “eternal” are derived from English and Latin translations of the Greek word “aionos” (Strong’s G166) which means age-enduring. For example, according to Revelation the Beast and False Prophet shall be punished for longer “aionas ton aionon (literally “ages of ages” or multiple ages –Rev20:10). All this is considered in more detail in my book (free PDF HERE)
Illustration – The Sistene Chapel painting: “The Final Judgement”