This article gathers a couple of comments I posted on "Called to Communion" on July 21-22, 2010.
First of all, "salvation" here is understood in the Roman Catholic sense of "sharing in divine life", "partaking in divine nature" (which is at the very least roughly equivalent to the Eastern Orthodox concept of "theosis" if we leave aside the essence-energies distinction, see 2 posts forward), and definitively not in the "ad extra", forensic justification sense.
Having said that, let's see what the Scripture says about the role that good works play in our salvation.
First of all, Jesus Himself makes it unequivocal that good works are necessary to remain in salvation. This is stated in positive statements in John's Gospel, chapters 14 and 15:
“Whoever has my commandments and observes them is the one who loves me. And whoever loves me will be loved by my Father, and I will love him and reveal myself to him.” (Jn 14:21)
“Whoever loves me will keep my word, and my Father will love him, and we will come to him and make our dwelling with him.” (Jn 14:23)
“Remain in my love. If you keep my commandments, you will remain in my love, just as I have kept my Father’s commandments and remain in his love.” (Jn 15:9-10)
“You are my friends if you do what I command you. … This I command you: love one another.” (Jn 15:14,17)
The Apostle John, in turn, makes the same concept clear in negative statements in his first letter:
Everyone who hates his brother is a murderer, and you know that no murderer has eternal life remaining in him. (I Jn 3:15)
If someone who has worldly means sees a brother in need and refuses him compassion, how can the love of God remain in him? (I Jn 3:17)
And as if all the above were not enough, there is this gem from Paul:
And whoever does not provide for relatives and especially family members has denied the faith and is worse than an unbeliever. (I Tim 5:8)
Now, besides being necessary to remain in salvation, do good works also add to salvation, meaning that by performing them we grow in God's life and love and consequently will be rewarded a greater degree of glory in Heaven?
Let’s listen first to the Teacher Himself:
“And whoever gives only a cup of cold water to one of these little ones to drink because he is a disciple–amen, I say to you, he will surely not lose his reward.” (Mt 10:42)
This is expanded in the Last Judgment passage, which I will not quote for obvious length reasons (Mt 25:31-46). And if it were argued that what this passage says is that works of charity are necessary to remain in salvation but do not add to salvation, the previous parable where the talent of the lazy servant was given to the servant who already had ten talents should clear the matter.
“Sell your belongings and give alms. Provide money bags for yourselves that do not wear out, an inexhaustible treasure in heaven that no thief can reach nor moth destroy.” (Lk 12:33)
“There is still one thing left for you: sell all that you have and distribute it to the poor, and you will have a treasure in heaven. Then come, follow me.” (Lk 18:22)
Let’s now go to Paul. First, this exhortation to Timothy is an exact echo of the last two quoted exhortations by Jesus:
Tell them to do good, to be rich in good works, to be generous and ready to share, thus storing up treasure for themselves as a good foundation for the future, so that they may take hold of that which is truly life. (1 Tim 6:18-19)
The following passage also uses the figure of the foundation, but now in the more conventional way of applying it to Jesus Christ:
But each one must be careful how he builds upon it, for no one can lay a foundation other than the one that is there, namely, Jesus Christ. If anyone builds on this foundation with gold, silver, precious stones, wood, hay, or straw, the work of each will come to light, for the Day will disclose it. It will be revealed with fire, and the fire (itself) will test the quality of each one’s work. If the work stands that someone built upon the foundation, that person will receive a wage. But if someone’s work is burned up, that one will suffer loss; the person will be saved, but only as through fire. (1 Cor 3:10-15)
Sometimes the Apostle uses the metaphor of a temple, which God builds with our cooperation, and other times he uses the metaphor of a body, which God makes grow with our cooperation. Sometimes both are used simultaneously, as in Ef 4:11-16, from which I quote:
Rather, living the truth in love, we should grow in every way into him who is the head, Christ, from whom the whole body, joined and held together by every supporting ligament, with the proper functioning of each part, brings about the body’s growth and builds itself up in love. (Ef 4:15-16)
Then there is this:
we do not cease praying for you and asking that you may be filled with the knowledge of his will through all spiritual wisdom and understanding to live in a manner worthy of the Lord, so as to be fully pleasing, in every good work bearing fruit and growing in the knowledge of God, (Col 1:9-10)
which is related to:
make every effort to supplement your faith with virtue, virtue with knowledge, knowledge with self-control, self-control with endurance, endurance with devotion, devotion with mutual affection, mutual affection with love. If these are yours and increase in abundance, they will keep you from being idle or unfruitful in the knowledge of our Lord Jesus Christ. (2 Pe 1:5-8)
As the last two quotes mention “knowledge”, let’s learn from Jesus what that is:
“Now this is eternal life, that they should know you, the only true God, and the one whom you sent, Jesus Christ.” (Jn 17:3)
If this knowledge is eternal life, it cannot be purely intellectual. This is made crystal clear by John in his first letter:
Whoever says, “I know him,” but does not keep his commandments is a liar, and the truth is not in him. (I Jn 2:4)
Beloved, let us love one another, because love is of God; everyone who loves is begotten by God and knows God. Whoever is without love does not know God, for God is love. (I Jn 4:7-8)
So, if salvation is having eternal life, and if eternal life is vital knowledge of God, and if by “living in a manner worthy of the Lord”, i.e. “living the truth in love”, we “in every good work bear fruit and grow in the knowledge of God”, then by good works we not only remain in salvation but also grow in salvation = eternal life = God’s love. As John says:
if we love one another, God remains in us, and his love is brought to perfection in us. (I Jn 4:12)