"He who is spiritual can perceive the hand of God in every event,
and therefore is able to forgive those who wrong him."
Allen P. Ross, "Genesis" in Bible Knowledge Commentary Old Testament,
USA: SP Publications, 1989, 94.
Joseph went through a lot of painful circumstances because of his brothers. Their hatred for him had almost led to his murder, and eventually led them to sell him as a slave. During his time as a slave, he was accused of rape, was thrown into prison, and forgotten by those he had helped. And yet, after all these bad experiences, Joseph still remembered the dreams God had sent him about the future. And now confronted by the presence of his brothers, he could see God's hand in everything that had happened — the good and the bad. He was thus able to forgive his brothers knowing that not only had God's plan been fulfilled through their actions but they had also repented of their sins against him.