There are variations of the story of an old man in his late 90’s who decides to go out and plant an apple tree. The onlookers are confused because the growth of the tree will take time and he presumably will be dead before he can see the fruits of his labor. It is at that moment the man explains that he is satisfied with just planting the seed knowing that someone else will be able to enjoy the delicious fruit after he is gone. Consequently, the old man is seen as the model of simplicity and humility.
This little story is often applied to the spiritual life. When we are doing something with God like evangelization or intercessory prayer, we should not seek the fruit of our labor as an end. If we did, that would contradict the self-giving nature of love, because acts of love should be done only thinking of the good of the other. Otherwise selfishness can creep in and corrupt the loving act, or at least taint it. This can be a hard lesson. Yet, all of our time on this Earth is for the singular purpose of learning how to truly love (giving ourselves completely without expecting anything in return). This is why Jesus and Mary are the apex of human existence. Both surrendered to the will of God and completely emptied themselves for the good of others and to honor God, and their journey led them to the cross where both gave without an expectation of receiving.
Yet, the cross is also where the analogy of the old man and his apple tree falls short. Because in Christianity, the cross is not the end. The resurrection is just around the corner. While after his death, the man will not be able to share in the fruits of the tree he planted, we as the mystical Body of Christ will be able to experience the glory that we have given God in our selfless love in eternity. God does not leave self-giving love unrewarded. Additionally, the whole Body of Christ glories in the successes in all of its members because our Heavenly Father is given glory in every act of love. So while the old man will never taste his delicious fruit and is only comforted by the fact that someone else will enjoy it, the Christian, even if they show a true act of completely selfless love, will be glorified by God. Jesus is the greatest example of this when His death on the cross merited not only the resurrection, but the seat at the right hand of the Father (bringing humanity with Him).
So the goal of the Christian is simple, yet difficult: We are to treat everyday as a school of love. We must live striving to encounter each person with the self-giving love of God. We cannot do this on our own due to our sinful nature. This can only be done if we allow ourselves to be changed by encountering Jesus in His sacramental presence. The sacraments are the fruits of Jesus born by His death nailed to a tree, and when we partake of that fruit, we ourselves are grafted onto His tree, become one with Him, and can bear much fruit just like Him. As Paul teaches us he who plants and he who waters are one. We may all work together for God’s glory, planting and nurturing seed, but it is only God who causes growth and will reward His coworkers in this life and/or the next.