Hadith 1022
وَعَنْ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسلم يَقُول: «مَنْ صَلَّى صَلَاةً يَشُكُّ فِي النُّقْصَانِ فَلْيُصَلِّ حَتَّى يشك فِي الزِّيَادَة» . رَوَاهُ أَحْمد
‘Abd ar-Rahman b. ‘Auf said that he heard God’s Messenger say,“If any of you prays a prayer and is in doubt whether it is deficient, he should go on praying till he begins to wonder whether he has not prayed too much.” Ahmad transmitted it.