It is narrated from Sayyiduna Suwayd Abu Abdullah al-Alhani (may Allah be pleased with him), who belonged to a branch of the Ash'aris. His son Abdullah bin Suwayd said: I heard the Messenger of Allah (peace and blessings be upon him), or someone who heard him (peace and blessings be upon him) told me, that he (peace and blessings be upon him) said: "Indeed, Allah has made this tribe of Lakhm and Judham a source of relief (for people) in Syria (al-Sham) through riding animals and milk, just as Allah made Yusuf (peace be upon him) a source of relief for its inhabitants in Egypt."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6442