صحیح ابن حبان
Ibn Hibban
كتاب الصلاة
Book of Prayer
باب فرض متابعة الإمام - ذكر الرخصة للداخل المسجد والإمام راكع أن يبتدئ صلاته منفردا ثم يلحق بالصف عند الركوع فيتصل به
Chapter on the Obligation to Follow the Imam – Permission for One Who Arrives While the Imam is Bowing to Start Alone and Join the Row During Ruku
1 hadith
Hadith 2194
Hasan narrates: Sayyiduna Abu Bakrah (may Allah be pleased with him) entered the mosque while the Prophet Muhammad (peace and blessings be upon him) was in bowing (ruku‘), so he also went into ruku‘ and then, while walking, joined the row. The Prophet Muhammad (peace and blessings be upon him) said to him: May Allah increase you in eagerness, but do not do this again.