Psalms 86:13

For great is thy mercy toward me: and thou hast delivered my soul from the lowest hell.

This is part of David's prayer in Psalm 86, set among Psalms 84-87 where Psalms 84 and 85 and 87 are psalms of the sons of Korah, and it stands alongside Matthew 3 through Matthew 8, including the Sermon on the Mount and the miracles of Christ in Matthew 8. The words “hell” and “lowest hell” translate the Hebrew word sheol, which the King James Version renders as “hell” here.

Sheol is rendered hell, grave, and pit in the Old Testament and is the same word translated hades in the New Testament. It means grave, sepulchre, hollow underworld, underworld, or state of the dead, the common state or receptacle of the dead. The deliverance in the verse is deliverance from the grave and the state of the dead, not from a place of torment or endless torment.

By great mercy God delivered the soul or life from sheol, rescuing it from death and its power and from the danger of going down there. Had God not kept the speaker alive, his soul would have gone to sheol, and a soul can be saved from going down to sheol. The deliverance was recovery from dangerous, life-threatening sickness, as shown alongside Psalm 30:2-3 where deliverance from sheol means recovery from such sickness.