Most evangelical churches communicate their purpose in terms of a cycle: usually a salvation component, a discipleship component, and an envangelization component, like grow, serve, reach… win, equip, share… glorify God by making fully devoted disciples… etc. Other churches communicate it through their ethos in oft-repeated statements like, “We are blessed so that we can bless.”
There is one sort of organism which seems to possess this kind of cyclical process: a virus. They seem to exist only in order to spread. Biologists question whether to regard viruses as fully living organisms or not.
I do not deny that the purpose of God for man always includes a desire that he would go out, that he would bless others by his blessing. There is indeed something utterly outpouring, something outwardly oriented and abundant, in the nature of God’s love within the trinity. The most natural thing, the inevitable thing, when filled with this love is to move outward, to want to tell it and give it and dance in the streets with it.
But I wish this kind of love were articulated more often in terms of sonship and family, of abundant life rather than replicating machine. What I mean is: as a father I certainly and deeply want my daughter to bless others, and I want her to become the bearer of the truth and love that I am bestowing on her, in a world that will be hers after I am gone. I want her life shine for the glory of God. But I hesitate to frame this great desire as “her purpose” or the reason that I brought her into being. There is something much deeper, more ontological about her purpose–I want her to be simply because I love her and want her to be, because being is good (after all, God is pure being). She is a living being who, to the extent that she comes alive, will radiate life; but her purpose is not to spread life, so much as to be alive. She is an end in herself, because she is, in her very being, the expression of my joy and love. And that is the way I think that it is our purpose to evangelize: to use (hopefully correctly) Thomist language: it is an accidental, rather than substantial purpose, and thus not the most fundamentally descriptive of what our purpose is.
Keeping this distinction makes all the difference, because it is the difference between our approaching the modus operandi of our Christian life as fundamentally doers for God, or receivers of God. The Incarnation of Christ compels us to rejoice that we are indeed the means of God on the earth, but that is only because we are first and forever his ends.