Sayyiduna Abu Hurayrah (may Allah be pleased with him) says: "The stingiest of people is the one who is stingy with the salam, and the most incapable of people is the one who is incapable of supplication."
Abu Ya'la recorded it as a mawquf report at the end of a hadith, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأدعية / 17195