To whom shall I speak, and give warning, that they may hear? behold, their ear is uncircumcised, and they cannot hearken: behold, the word of the Lord is unto them a reproach; they have no delight in it. Therefore I am full of the fury of the Lord; I am weary with holding in: I will pour it out upon the children abroad, and upon the assembly of young men together: for even the husband with the wife shall be taken, the aged with him that is full of days. And their houses shall be turned unto others, with their fields and wives together: for I will stretch out my hand upon the inhabitants of the land, saith the Lord. For from the least of them even unto the greatest of them every one is given to covetousness; and from the prophet even unto the priest every one dealeth falsely.
Clearly, God could have given the citizens of Jerusalem ears to hear in 587BC, so that they repented, but he chose to withhold the gift of faith. Why? Obviously only God knows the answer to that question, and he chooses not to give it in the Bible; which is the only place we could look for a definitive answer. Nevertheless, it is possible to (cautiously) speculate, and the answer might be that he intended the destruction of Jerusalem to be a lesson for all future generations, including us living in 2015. If the scriptures were to serve their purpose in revealing God to us, it was necessary that they record his dealings with men in history, and, in particular, his response to their sin. God’s plan extends, after all, from the moment of creation, right up until the moment when the universe ceases to exist. On that vast time scale there is no reason to suppose that the Lord might not foreordain events in one age, so that reading about them in another age might have an effect upon those of his elect living perhaps millennia into the future.
Bringing judgement upon his creatures is not necessarily something God enjoys, but it may be that he is nevertheless prepared to foreordain sin, and the consequent punishment, in order to achieve the greater purpose of revealing himself, and his nature, to men.
“And we know that all things work together for good to them that love God.” (Romans 8.28)
“For a thousand years in thy sight are but as yesterday when it is past, and as a watch in the night.” (Psalm 90.4)
If we cannot understand why God has allowed some of the more horrific events in our own time, we should perhaps bear in mind that the answer may not be one to be found in our own lifetime, or, for that matter, in the lifetimes of many generations to come. “We are soon cut off, and fly away,” but God is “from everlasting to everlasting.”