Sahih al-Bukhari 613
Narrated Yahya as above (586) and added:
"Some of my companions told me that Hisham had said, "When the Mu'adh-dhin said, "Haiyi `alassala 
(come for the prayer)." Muawiya said, "La hawla wala quwata illa billah (There is neither might 
nor any power except with Allah)" and added, "We heard your Prophet saying the same."
حَدَّثَنَا إِسْحَاقُ بْنُ رَاهَوَيْهِ، قَالَ حَدَّثَنَا وَهْبُ بْنُ جَرِيرٍ، قَالَ حَدَّثَنَا هِشَامٌ، عَنْ يَحْيَى، نَحْوَهُ‏.‏ قَالَ يَحْيَى وَحَدَّثَنِي بَعْضُ، إِخْوَانِنَا أَنَّهُ قَالَ لَمَّا قَالَ حَىَّ عَلَى الصَّلاَةِ‏.‏ قَالَ لاَ حَوْلَ وَلاَ قُوَّةَ إِلاَّ بِاللَّهِ‏.‏ وَقَالَ هَكَذَا سَمِعْنَا نَبِيَّكُمْ صلى الله عليه وسلم يَقُولُ‏.‏