Sayyiduna Ibn Umar (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "Allah Almighty does not accept charity from wealth gained through treachery, nor (does He accept) prayer without purification."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 187
Abu al-Malih al-Hudhali narrates from his father (may Allah be pleased with him), who said: One day I was with the Messenger of Allah (peace and blessings be upon him) in a house, and he (peace and blessings be upon him) said: "Allah Almighty does not accept prayer without purification, nor does He accept charity from wealth gained through treachery."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 188
It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both): We were with the Prophet (peace and blessings be upon him). He (peace and blessings be upon him) went to the toilet, then he came back, and food was brought to him. It was said: "O Messenger of Allah, will you not perform ablution?" He (peace and blessings be upon him) said: "For what? When I pray, then I will perform ablution."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 189
It is narrated from Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) came out of the toilet and food was presented before him (peace and blessings be upon him). The Companions (may Allah be pleased with them) said: "Shall we not bring you water?" He (peace and blessings be upon him) said: "I have been ordered to perform ablution only when I intend to pray."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 190