Abd al-Rahman bin al-Harith bin Hisham narrates from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) used to make this supplication at the end of his witr:
'Allahumma inni a'udhu bi-ridaka min sakhatik, wa bi-mu'afatika min 'uqubatik, wa a'udhu bika mink, la uhsi thana'an 'alayk, anta kama athnayta 'ala nafsik'
(O Allah, I seek refuge in Your pleasure from Your anger, and in Your pardon from Your punishment, and I seek refuge in You from You. I cannot enumerate Your praise; You are as You have praised Yourself.)
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4871