JI Packer in A Quest for Godliness:
It cannot be over-emphasized that we have not seen the full meaning of the cross till we have seen it as the center of the gospel, flanked on the one hand by total inability and unconditional surrender and on the other by irresistible grace and final preservation.
Christ died to save a certain company of helpless sinners upon whom God had set his free saving love. Christ’s death ensured the calling and keeping — the present and final salvation — of all whose sins he bore. That is what Calvary meant, and means. The cross saved; the cross saves.