The Messenger of Allah ﷺ said, "Whoever performs ablution well, then sets out for the prayer only to find that the people have already prayed, Allah the Mighty and Majestic grants him a reward equal to that of those who prayed and attended, without diminishing their reward in the least."
حدثنا عبد الله بن مسلمة حدثنا عبد العزيز يعني ابن محمد عن محمد يعني ابن طحلاء عن محصن بن علي عن عوف بن الحارث
قال رسول الله ﷺ من توضأ فأحسن وضوءه ثم راح فوجد الناس قد صلوا أعطاه الله جل وعز مثل أجر من صلاها وحضرها لا ينقص ذلك من أجرهم شيئا
[Hasan] Reported by Nasai, chapter on the leader of prayer, section on the minimum for catching the congregation, no. 856, from the hadith of Abdul-Aziz bin Muhammad Darawardi with this wording. Hakim graded it sahih in 1/208, 209, and Dhahabi agreed with him.