It is narrated from Sayyiduna Sahl bin Sa'd (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "There is no ablution (wudu) for one who does not send blessings upon the Prophet (peace and blessings be upon him)."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5677