There are three things you can’t do alone: be yourself, be a disciple, and be the church.
All the “one another” passages in the Bible make it clear that God’s mission is to form, not solely individuals, but a people. Furthermore, implicit in the Great Commission to go and make disciples is to be made a disciple. We cannot reproduce disciples if we are not ourselves disciples first. So, being made a disciple and being formed as a people are not possible apart from “one another,” apart from life together with other disciples.
It is our love for one another, our relationships with one another, that will bear witness to the world that we are disciples of Jesus. Yet, not only our relationships with those like us, but especially with those who are different from us.