How does grace relate to the formation of covenant in Christianity?

In the Christian understanding, the covenant is deeply rooted in grace, as established in God's eternal plan for His chosen people. Ephesians 1:4-5 indicates that God predestined His elect in grace, with Christ assuming the role of surety or mediator in the covenant. This means that Christ guarantees all promises made by God to His people and fulfills the obligations of the covenant on their behalf. Thus, salvation is treated as an everlasting covenant of grace, emphasizing that it is not through human effort but through Christ's obedient work that believers are redeemed and brought into a relationship with God.