أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ مُحَمَّدٍ، عَنِ ابْنِ طَحْلاَءَ، عَنْ مُحْصِنِ بْنِ عَلِيٍّ الْفِهْرِيِّ، عَنْ عَوْفِ بْنِ الْحَارِثِ، عَنْ أَبِي هُرَيْرَةَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ مَنْ تَوَضَّأَ فَأَحْسَنَ الْوُضُوءَ ثُمَّ خَرَجَ عَامِدًا إِلَى الْمَسْجِدِ فَوَجَدَ النَّاسَ قَدْ صَلَّوْا كَتَبَ اللَّهُ لَهُ مِثْلَ أَجْرِ مَنْ حَضَرَهَا وَلاَ يَنْقُصُ ذَلِكَ مِنْ أُجُورِهِمْ شَيْئًا ‏"‏ ‏.‏

It was narrated from Abu Hurairah that the Messenger of Allah (PBUH) said: "Whoever performs wudu' and does it well, then sets out for the Masjid and finds that the people have already prayed, Allah will decree for him a reward like that of those who attended (the prayer), without reducing the slightest from their reward." Translation Not Available

Book Ref: Sunan An Nisai Book 10 Hadith 855
Web Ref:  Sunan An Nisai Vol 1 Book 10 Hadith 856