When Yaakov sends Yosef to “check” on his brothers there are two unusual pesukim are mentioned in between Yaakov’s command and Yosef’s arrival of his brothers:
טו) וַיִּמְצָאֵהוּ אִישׁ וְהִנֵּה תֹעֶה בַּשָּׂדֶה וַיִּשְׁאָלֵהוּ הָאִישׁ לֵאמֹר מַה תְּבַקֵּשׁ
15. Then a man found him, and behold, he was straying in the field, and the man asked him, saying, “What are you looking for?”
טז) וַיֹּאמֶר אֶת אַחַי אָנֹכִי מְבַקֵּשׁ הַגִּידָה נָּא לִי אֵיפֹה הֵם רֹעִים
16. And he said, “I am looking for my brothers. Tell me now, where are they pasturing?”
This encounter separates Yaakov’s command to his son to seek out his brothers and the sale of Joseph to passing merchants.
The Ramban tells us that this unidentified man is the angel Gabriel ensuring that history plays itself out. Illustrating Divine providence in this story.
The question remains – If Jacob knows that the brother hate Joseph why does he send him to the front lines?
Why does G-d intervene and guarantee that Joseph is placed amongst his adversaries? What did Yosef need to experience to ensure his own future and the future of the Jewish people (see the Rashbam ad loc. on Yosef’s strength in this situation)?