If we listen to current debate in the church (clearly a debate we have been having since the time of Jesus) it seems it is easy to lose Jesus' dual focus of loving God and loving our neighbour. Of course, everyone says they are being faithful to the command of Jesus, but the liberal left have the tendency so to unite the two that Christianity ends up social work/peace & justice work with a veneer of God, whereas the conservative right have a tendency to separate the two, and then subordinate love of neighbour to love of God. Although Jesus does indeed put the two in that order (Mk 12:29-31), if hierarchicalized in this way the bald statement of the two greatest commandments as a summary of the whole law is not an adequate basis on which to build our practice of the two greatest commandments. The Johannine corpus makes it clear that loving God cannot be divorced from loving neighbour. (1Jn 4:7-21) This unity of love is also at the heart of the washing of the feet. Jesus' command, after showing his love for the disciples by washing their feet, is not to command a pietistic love of himself (i.e. of Jesus), but a command for them to wash one another's feet. (Jn 13:14) St Paul is explicit on this point when he says that the whole law is summed up in a single commandment, "You shall love your neighbour as yourself." (Gal 5:14; Rom 13:8-10). And James is following Jesus when he says that our faith is shown through our love of neighbour. (Jas 2:8-26).
How to hold the two together? The answer is Jesus of course, and specifically thinking here of his dual unity of person in two natures. As in so many things Christian, we hold together that which might otherwise be torn asunder. The doctrine of the Incarnation is the greatest expression of this, and is now our guiding principle in application of a theology of union. In the case of uniting love of God and love of neighbour, we should remember that the divinity of Jesus is inferred from the kind and quality of his human life. But this does not mean that his humanity is merely a cipher for his divinity (a problem with the Christian right) or that we can, in practical terms, ignore his divinity (a problem for the christian left). In a parallel fashion, we cannot love God apart from our human neighbour, yet in loving our neighbour wed should not ignore God.
A practical result is to be found in the Eucharist. The Eucharist makes no sense without our neighbour (why a priest cannot preside at the Eucharist alone), and not just the neighbour in the pew next to us. We bring our love of neighbour practised during the week to the liturgical expression of our love of God. (Not just the other way around.) When we do this bloodless piety is transformed into a genuine thanksgiving for what God's enfleshment in Jesus and his death and resurrection has won for us. We are able to love God's flesh and our neighbour's flesh, and vice-versa.
