How do we know the sure mercies of David are for us?

Isaiah 55:3 speaks of the 'sure mercies of David,' which are tied to the everlasting covenant made by God. This covenant is fulfilled in Christ, who is the surety and mediator of God's promises. The mercies bequeathed to God's chosen people ensure that they receive reconciliation, justification, forgiveness, and adoption as children of God. These mercies are secure, as they are rooted in the work of Christ, who accomplished everything required for our redemption. In light of this, believers can confidently lay hold of these promises, knowing they are founded on the faithfulness of God to His covenant.