John 13
"A new commandment I give to you, that you love one another even as I have loved you ... by this all men will know that you are My disciples" (v34). The Old Testament taught people to love their neighbors, but Jesus demonstrated love beyond anything the world had ever seen. Knowing the human tendency to use position to dominate others, Jesus washed His disciples' feet. "If I then, the Lord and the Teacher, washed your feet ..." (v14).
When we love each other like our Teacher demonstrated, humbly serving one another, the world notices.