I'm thinking in particular of phenomena like xenophobia (racism) and homophobia. These seem to involve an unpleasant mix of fear and hatred, apparently without rational motivation. My guess is that these spring from the recognition that the other person is different from me, combined with the recognition (perhaps suppressed) that they are not all that different. I suspect it is hard to have this strength of feeling unless some proximity is felt - if the other were completely different, there would be a lot less threat implied by their existence. So this is all just one example of the complex relationship with "the other". The other is like me and yet unlike; unlike and yet disturbingly like.
The gospel seems to me to speak into this situation by affirming and bringing into the light the "likeness". By introducing us to "The Other" - God in Christ - the gospel makes it clear that the most fundamental thing about each of us is that we stand before someone utterly unlike us, our Creator. In that situation, we are all the same. Our differences do not register when measured against this absolute scale.
But this would not be sufficient by itself, I suspect, to overcome our fear of one another. Something more is needed, and that something more is the fact that God has become one of us - has entered into the sphere of particularity and difference. Jesus had a particular ethnicity, sexuality, gender. He was like and yet unlike. And yet his universal appeal, and universal love, serve in this sphere also to relativise our differences.
So the point is: there is no difference. All stand the same before God, in the sphere of absolute and relative "difference".
Connected thought: some will object to me lumping racism and homophobia together. I don't do that in the way that the secularist does; indeed, I reject the connection in the way that the secularist sees it. For me, homosexuality remains an ethical issue, because it is an ethical issue in the Scriptures. But even here, the difference is relativised. How can the Christian be homophobic when "such were some of you"? How can there be fear and hatred here when there is no difference except what God has made by graciously removing you from that sphere to this?
Another connected thought: the only absolute difference is one found outside the relationship between me and the other human beings. It is found in God, in Christ. Therefore it is not my business to prosecute this difference, but to entrust the management of it to him and in the meantime to love.