It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever sees me in a dream, let him be certain that he has indeed seen me, for Satan cannot assume my form before anyone."
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 2525
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا إسناد ضعيف لضعف جابر الجعفي