Joseph becomes overwhelmed with sadness following the realization that his brothers have not been enjoying their relationship with him due to the fact that they did not truly believe they were forgiven. He then reassures them that despite the circumstances he faced in regards to his brothers, God transformed it for his good. He later passes away and asks his brothers to take his bones to the promised land.
Joseph's weeping mirrors the time when Jesus wept. We are reminded in Genesis 50 that Jesus died on the cross once to wipe away our sins forever. We are reminded of how much of a blessing God's commitment to forget is.