«إذا صلى أحدكم في بيته ثم دخل المسجد والقوم يصلون فليصل معهم تكون له نافلة»
The Prophet (peace and blessings be upon him) said:
"When one of you has prayed in his house and then enters the mosque while the people are praying (in congregation), let him pray with them; it will be a voluntary (nafl) prayer for him."
Hadith Referenceصحیح الجامع الصغیر / حرف الألف / 654
Hadith Gradingالألبانی:صحيح
Hadith Takhrij[طب] عن عبد الله بن سرجس. الإرواء ٥٣٤.