In Genesis 37 12-20, if Joseph was so important to Jacob, why did he allow him to travel so far alone when he knew there were problems with his brothers? And who was the stranger he meet in the fields, that knew so much about them? Also in 1 Samuel 16 5-13
why was David not invited to the dinner with the other boys, but had to be asked to come?
Could it be like Joseph, the brothers didn’t care for David?
These are excellent questions and have been addressed by the Sages and Commentators.
It never dawned on Jacob that his sons would act as they did. Even though he was aware of the tensions, murder or sale into slavery was not something he imagined his sons would do. Remember, even after the fact, over the course of the 22 years in which Jospeh was gone, he never suspected that he had met with foul play on the part of the brothers.
The sages teach us, on the basis of a comparison with other verses, that the man he met was the angel Gabriel.
David was not invited to the dinner as they did not consider him to be part of the family. Some say that there were questions as to his paternity.