When the brothers of Sayyidna Yusuf (علیہ السلام) requested their father that he should send Yusuf with them on a recreational outing, Sayyidna Ya'qub (علیہ السلام) told them that he did not favour sending him out for two reasons: (1) He remains uncomfortable without him in sight and (2) he apprehends that, in the wilderness out there, it might so happen that they become neglectful at some time and a wolf might eat him up.
The apprehension of Sayyidna Ya'qub may have been caused either due to the abundance of wolves in Canaan, or because he had seen in a dream that he is standing on top of a hill and Sayyidna Yusuf (علیہ السلام) is there on the slope downhill. All of a sudden ten wolves surround him and try to attack him. But, one of the wolves came forward to rescue him from the rest. Once released, Sayyidna Yusuf علیہ السلام took refuge inside the terrain.
The interpretation of that dream manifested later when it turned out that the ten wolves were these ten brothers and the wolf which defended Sayyidna Yusuf (علیہ السلام) and saved him from being killed was his elder brother, Yahuda (Judah). And the depth of the pit was the interpretation of his hiding under the land.
In a narration from Sayyidna ` Abdullah ibn ` Abbas ؓ ، it has been reported that Sayyidna Ya` qub (علیہ السلام) ، because of this dream, felt the danger of an unfortunate situation coming at the hands of these brothers. Thus, in fact, they were the ones he had alluded to as wolves - but, in consideration of his wisdom, he did not lay the truth bare. (Qurtubi)