All the peoples in all times knew well by their own bitter experiences that the power of the world of darkness, which is called in the Bible Sheol, is absolute over man. In fact, no matter the number of years man lived on earth, his life turned out always temporary, but here is, the world of darkness, the kingdom of dead, which waits for everyone at the end of his earthly way, absorbed him for ever. Besides, there was nothing comforting in this world: one could call life the existence, which man had there only with a lot of effort: neither a full self-consciousness, nor the memory to man remained in the in the world of the darkness. And here is the authors of the biblical books begin to guess that the power of the sheol, the world of darkness is not absolute over man, that it surmountable, and surmountable only with God’s help.
The idea of the possibility of a general resurrection in the last day becomes common, of course, already in the period after captivity, but the first intuitive conjectures on it probably began to appear to certain people even before the captivity. What served as basis for the hope to overcome the power of sheol? Perhaps, the history of Abraham, who, having experienced on himself the power of the world of darkness, freed himself of this power with God’s help. And perhaps, the prophetic experience: because the prophets as nobody else deeply experienced the reality of that life-giving breath of God, without which man does not exist as image of God. Be that as it may, even before captivity in the yahviste community there was apparently the understanding of the fact that God and death are incompatible.
The Kingdom of God, no matter how it was understood in the period before captivity, was by definition the kingdom of life, besides life in all its fullness. But the sheol, the world of darkness, was, on the contrary, the kingdom of death, a world, where it was impossible to live and was not giving to man to totally die, in order to go once and for all into nothingness.
It is not surprising, that such a humiliation similar to the life with God's mercy in the consciousness of the believers didn’t match in any way. And it is this confidence in God's mercy which became apparently the basis of this confidence expressed in the psalm to overcome the death and the power of the sheol, the world of the darkness over man. And after, already after the captivity, this confidence took the form of faith in a general resurrection.