35 This proper way of serving others also leads to humility. The one who serves does not consider himself superior to the one served, however miserable his situation at the moment may be. Christ took the lowest place in the world—the Cross—and by this radical humility he redeemed us and constantly comes to our aid. Those who are in a position to help others will realize that in doing so they themselves receive help; being able to help others is no merit or achievement of their own. This duty is a grace. The more we do for others, the more we understand and can appropriate the words of Christ: “We are useless servants” ( Lk 17:10). We recognize that we are not acting on the basis of any superiority or greater personal efficiency, but because the Lord has graciously enabled us to do so. There are times when the burden of need and our own limitations might tempt us to become discouraged. But precisely then we are helped by the knowledge that, in the end, we are only instruments in the Lord's hands; and this knowledge frees us from the presumption of thinking that we alone are personally responsible for building a better world. In all humility we will do what we can, and in all humility we will entrust the rest to the Lord. It is God who governs the world, not we. We offer him our service only to the extent that we can, and for as long as he grants us the strength. To do all we can with what strength we have, however, is the task which keeps the good servant of Jesus Christ always at work: “The love of Christ urges us on” ( 2 Cor 5:14).
Source: Deus Caritas Est (Vatican.va)