It is narrated from Hazrat Abu Hurairah (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: The prayer of the person who does not have ablution is not accepted, and the ablution of the one who does not begin with the name of Allah is not valid.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 9418
Hadith Gradingحکم دارالسلام:إسنادہ ضعیف لجھالة یعقوب ، و والدہ سلمة