"Love one another" seems like the simplest of commandments, but it's actually one of the most complex. When the Christian Tradition tells us that Jesus said to "love one another" does it mean "love" in the same way I mean "love" or in another way.
Who is the "other" at present? Sure, for Jesus' disciples it was "one another", a.k.a., the other disciples, but those men are dead and gone. If the "commandment" has life it must have life in the present. And if it has life in the present I must reapply it to a new situation with new recipients of my love.
Many preach that this is a call for Christian unity: love other Christians. Seems simple enough, but after two millennia other Christians aren't always the people I see as "brothers and sisters" in this world by default. Many who bear the title "Christian" are cruel and unjust to others. Do they deserve my love more than those whom they mistreat simply because they claim to that Jesus is their "Lord and Savior"?
Does the command to "love one another" find more perfect fulfillment when it is universalized, as much as possible, beyond the boundaries of family, nation, and creed? In Jesus' day it may have been radical to call together a new family, asking his followers to love one another in a way that transcended their previous loyalties. Might it be that to retain the spirit of a day like Maundy Thursday we must move beyond a rigid, literalistic application of "love other Christians" toward a broader, counter-cultural, in-group transcending love of as many people as we can love, both familiar and strange? Whatever the answer, it remains a difficult task, for loving is never quite as easy as it sounds.