Why is resting in Christ essential for salvation?

In sovereign grace theology, salvation is viewed as a work entirely accomplished by Christ, necessitating that believers rest in His promises for assurance of their salvation. This rest implies that individuals can do nothing to earn or maintain their salvation; it is solely dependent on Christ's atoning sacrifice. John emphasizes that true assurance comes from resting confident in Christ's work rather than in personal efforts or moral achievements. This resting posture reflects a deep trust in the sovereignty of God, recognizing that He is the one who keeps believers secure in their salvation. Thus, the call is to abandon reliance on self and fully embrace Christ as the foundation of faith and hope.