Joseph returns having removed any trace of his strong feelings; it is essential that at present they do not know who he is, for he has further important lessons to teach them, and the sight of him weeping would have been so strange, that even they might have questioned who he really was. The seating arrangement was unusual, but, as Calvin says, was organised by Joseph.
In dealing with a lost soul, Christ cannot reveal his personal love for our souls too early, before he has brought us to true repentance. We must die to sin, or else God’s grace will be taken advantage of: we will sin that grace may abound. Only the one who has been through the experience of Romans 6 can safely be shown the full extent of Christ love and grace. Before that, the lessons he has to teach us rely on us grasping what we deserve at the hands of justice. The preacher preaches the gospel, and tells us of the possibility of forgiveness, but the Spirit does not cause us to grasp hold of God’s mercy, until we are convinced that it is our greatest need.