I had problems at first coming to Jesus about all the death sentences and commands to wipe out all the inhabitants of ancient cities. I mean, women and children. God is higher than we are.
Isa. 55:8,9 "For my thoughts are not your thoughts, neither are your ways my ways, saith the LORD. For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts."
It makes it seem so cruel is that God is condemning them to forever flames according to our traditional Christian understanding. God is not doing that. In fact, if a person is not called of God in this first dispensation his whole life is vain and meaningless.
Ecc. 1:2 "Vanity of vanities, saith the Preacher, vanity of vanities; all is vanity."
Ecc. 1:14 "I have seen all the works that are done under the sun; and, behold, all is vanity and vexation of spirit."
Ecc. 2:17 "Therefore I hated life; because the work that is wrought under the sun is grievous unto me: for all is vanity and vexation of spirit."
Ecc. 3:19 "For that which befalleth the sons of men befalleth beasts; even one thing befalleth them: as the one dieth, so dieth the other; yea, they have all one breath; so that a man hath no preeminence above a beast: for all is vanity.
Ecc. 12:8 "Vanity of vanities, saith the preacher; all is vanity."
God looks at life and death differently than we do. We spend all our time trying to make sure our needs are met. We work tirelessly to make sure we have food, shelter and clothes for tomorrow. We worry and fret and save for hard times because we have seen them come. All of this is against faith (see Matt. 6:25).
When this life ends, nobody is headed to "forever" flames. This is why there is no understanding what God is doing. When Christ comes back, mainstream Christianity will be treated much like the Pharisees of the first century. It will be a case of a different Christ than what was expected.