What does it mean that Christ's sacrifice was once and done?

The phrase 'once and done' refers to the sufficiency and finality of Christ's sacrifice for sin. Hebrews 9:26 states that Christ appeared once at the end of the age to put away sin by the sacrifice of Himself. This signifies that His death on the cross was a one-time event that fully satisfied the demands of justice for all His people. Unlike the repeated sacrifices of the Old Testament, which were temporary and required continual repetition, Christ's sacrifice was effective from the beginning and for all eternity. This truth provides the assurance that believers are fully redeemed, justified, and cleansed before God, with no further sacrifice needed for the forgiveness of sins.