Thanks Pilgrim.
I don't understand what you mean when you wrote,"v. 20 The description now introduces particulars of the Messianic kingdom, stressing the longevity of those who will belong to that kingdom. From there may refer to Jerusalem, the thought being that There will not be from there (i.e., taken away from there by death) a suckling with respect to days. Thus, death will not take away from there (i.e. from the Jerusalem of the Messianic age) one who is merely a suckling child as death is now wont to do. Nor will the elderly man who has not yet lived out the full span of life meted to him be taken away by death as is now the case.

In the second part of the verse the opposite truth is express. The youth who is one hundred years old will die, i.e., when one dies at the age of one hundred, he shall be regarded as merely a youth, the implication being that he had yet far more life to live. Likewise, when death cuts of a sinful man, it does so when he has lived a hundred years. Men will die, and death is a curse and when that curse comes as a punishment for sin, as it does even to God's people, the sinner will be a hundred years old. Thus, one of the blessings of the new age is that of longevity. Basic to this promise is probably the conception already expressed in Genesis 53. The conditions of Paradise are to be restored, but the new age will surpass Paradise."

The Messianic Kingdom you say the passage refers to in your first paragraph presumably is not yet because these conditions do not prevail now, but neither can they be taken to refer to heaven because there is no death in heaven. Could you explain further?

Thanks.