on rewards of good works
While the word merit or reward (Greek misthos) in the New Testament (cf. Matthew 6:2 & 5; Luke 6:23 etc.) also means wages (cf. Matthew 20:8, Luke 10:7, James 5:4) our relation with God is not like that of worker-employer. An employer needs a work to be done and workers deserve their wages for satisfactory completion of the work. In contrast God is far above us – He does not need us because He can do everything Himself. This means, strictly speaking, we cannot merit anything from God.
“With regard to God, there is no strict right to any merit on the part of man. Between God and us there is an immeasurable inequality, for we have received everything from him, our Creator. “
Catechism of the Catholic Church # 2007
Yet Scripture refer us as God’s workers (Matthew 9:37, Greek ergates), even as His co-worker (1 Corinthians 3:9, Greek sunergos). Why does God need us as workers if He can do everything Himself? To answer this question, we note that in standard worker-employer relation, merit (in this case wages) is not a gift but a worker’s due (cf. Romans 4:4). Our salary/wages/paycheque is not a gift from our company – we work for it and thus we deserve it. In contrast Catholics consider merit (of our good works) as a gift from God; in other word it is also God’s grace. “Our merits are God’s gifts” (Catechism of the Catholic Church # 2009) and “The saints have always had a lively awareness that their merits were pure grace” (Catechism of the Catholic Church # 2011). Catholics believe that our merit is a gift from God who wants us, using our freedom, to cooperate with His Grace. It is God’s Grace that first moves us to do good works and if we cooperate He will rewards us.
The following analogy (it came from Fr. Mitch Pacwa S.J., EWTN’s radio and television host) might help to explain Catholic understanding of merits from good works. Suppose a mother was baking a cake when her child came. She asked her child whether he/she wanted to help, which the child gladly agreed. Note that the mother does not need her child’s help – she can do the work herself. Out of her motherly love she allowed and even welcomed her child’s help. She then rewarded her child for his/her help (even if, instead of helping, he/she created an unintentional mesh), be it in the form of words of praises, a hug or a kiss. The merits of her child help is therefore a gift from the mother, not something he/she deserves. In the same way God can do any work Himself but He uses us, with our consent, to be His “workers”. He can rain down food and clothes from heaven to feed the hungry and to clothe the naked; but he wants us to do it. He can bring the good news of salvation to anybody on earth, regardless where the person lives – but He wants (some of) us to become missionaries. Recall again that Catholics believe it is God, through His Grace, who first moves us to do good works (be it loving one another, repenting, praying, witnessing, preaching, working as missionary etc.) and without His Grace, we cannot do it, not even have the initiative to do it. Paul wrote: Not that we are competent of ourselves to claim anything as coming from us; our competence is from God (2 Corinthians 3:5). Using our freedom, we choose either to cooperate or not with the given Grace. If we do, then God will reward us. Our rewards are therefore God’s gift or are also His Grace. Because our rewards are His gift then they may come in the form of another Grace and even eternal life.