Reasons why George travels with Lennie in chapter 3?

George confides in Slim about the reasons that he travels with Lennie. George knew Lennie's Aunt Clara. At times George would tease and humiliate Lennie for entertainment. George, however, began to understand the extent of Lennie's loyalty and fidelity to him. George understood that Lennie isn't crazy, he is just "dumb". George promised Aunt Clara that he would look after Lennie. The two now travel together where as other men live lonely insular lives.