Although the polytheist is impure (so how could he have ablution), and Abdullah bin Umar (may Allah be pleased with them both) used to prostrate without ablution.
Hadith Referenceصحيح البخاري / كتاب سجود القرآن / 1071
Although the polytheist is impure (so how could he have ablution), and Abdullah bin Umar (may Allah be pleased with them both) used to prostrate without ablution.