“The wicked will return to Sheol.” It is likely that the psalmist had in mind only that the wicked would return to Sheol (or be “turned back” to Sheol), in contrast to himself, who was lifted away from the gate of death. But the Hebrew text also presents an important eschatological truth, i.e., that the wicked do in fact “return” to Sheol. They live and die, going to Sheol, the state of death. But then in the Second Resurrection, they are judged unrighteous and thrown into the Lake of Fire and die there, returning to Sheol a second time (cp. Rev. 20:11-15).
[For more on the wicked dying in the Lake of Fire, see Appendix 5, “Annihilation in the Lake of Fire.”]