It is narrated from Sayyiduna Salman al-Farisi (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Allah, the Mighty and Majestic, is shy, when a servant raises his hands, to send them back empty with nothing in them."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6123