It is narrated from Sayyiduna Jabir (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) supplicated for rain and turned his cloak around, so that the drought would be turned around.
Thus he said it, 'from Jabir'; others narrated it from Ishaq bin Isa without mentioning Jabir in it, making it the saying of Abu Ja'far.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الاستسقاء / 6418
Ishaq bin Ibrahim says that Waki' explained, regarding his words that he (peace and blessings be upon him) put the right side of the cloak onto the left and the left side onto the right: that is, (it is a hope) that He turns drought into greenery, just as the cloak has been turned from the right side to the left side.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الاستسقاء / 6420