عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ رَضِيَ اللَّهُ عَنْهُ قَالَ: أَلَا أُحَدِّثُكُمْ بِحَدِيثٍ سَمِعْتُهُ مِنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ؟ قَالُوا: بَلَى، قَالَ: فَأَشْهَدُ أَنِّي سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَقُولُ: مَنْ صَلَّى صَلَاةً يَشُكُّ فِي النُّقْصَانِ فَلْيُصَلِّ حَتَّى يَشُكَّ فِي الزِّيَادَةِ))
Sayyiduna Abdur Rahman bin Awf (may Allah be pleased with him) said: Shall I not narrate to you the hadith which I myself heard from the Messenger of Allah (peace and blessings be upon him)? They said: Why not. He said: I bear witness that I heard the Messenger of Allah (peace and blessings be upon him) saying: Whoever performs prayer and doubts that it is deficient, he should continue praying until he begins to doubt that it is excessive.