It is narrated from Sayyiduna Anas (may Allah be pleased with him): I saw the Companions (may Allah be pleased with them) being woken up for the prayer, and I would hear the sound of their snoring; then they would stand up and pray, and they did not perform ablution.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 592