Romans 5:10

For if, while we were enemies, we were reconciled to God through the death of his Son, much more, being reconciled, shall we be saved by his life.

This is a fuller statement of the argument made in the preceding verse, a conclusion of logic identified by Hodge as "a fortiori":

If the greater benefit has been bestowed, the less will not be withheld.[23]

Murray stated it more fully thus:

The "a fortiori" argument of the apostle is thus apparent. It is to the effect that if, when we were in a state of alienation from God, God showed us his love to such an extent that he reconciled us to himself and instated us in his favor through the death of his own Son, how much more, when this alienation is removed and we are instated in his favor, shall the exaltation of Christ insure our being saved to the uttermost. It would be a violation of the wisdom, goodness, and faithfulness of God to suppose that he would have done the greater and fail in the lesser.[24]

Saved by his life ... suggests the many things revealed in the New Testament that Christ is at the present time doing on behalf of the redeemed. He daily adds to the church those that are being saved (Acts 2:47); helps those who are tempted by providing a way of escape (1 Corinthians 10:13); provides mercy and grace to help in time of need (Hebrews 4:15,16); makes intercession for his own (Hebrews 7:25; 9:24); is expecting until all his enemies become the footstool of his feet (Hebrews 10:13); and he is, in fact, reigning over all things (1 Corinthians 15:25,26).

[23] Charles Hodge, Commentary on the Epistle to the Romans (Grand Rapids, Michigan: Wm. B. Eerdmans Publishing Company, 1968), p. 138.

[24] John Murray, op. cit., 1p. 175.