Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates: the Prophet (peace and blessings be upon him) said: "By the One in whose hand my soul is, whatever revelation Allah Almighty sent down upon any prophet, that revelation, between Allah Almighty and that prophet, was in the Arabic language; then, after that, that prophet would convey that revelation to his people in their own language."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains Sulayman bin Arqam, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 16603