Genesis 37:16

And he said, I seek my brethren: tell me, I pray thee, where they feed their flocks.

Jacob had sent Joseph to check on his brothers at the place where he expected them to be pasturing, Shechem, but Joseph did not find them there. At Shechem he asked where they were feeding their flocks, and a stranger told him they had gone to Dothan. He willingly went on to Dothan, undertaking the long journey and continuing despite his weariness.

His persistence showed obedience to his father and a desire to ease his father's worry and reassure him. It also showed genuine concern and love for his brothers and a desire to see them, even though they had been unkind to him. The meeting at Dothan that followed this search was later remembered by Joseph as the time when his brothers met his anguished pleas with angry looks and insulting words, before their deed separated him from home and made him a slave.