Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: I heard the Prophet (peace and blessings be upon him) say: "When a person enters the mosque while the imam is on the pulpit, then there is to be no prayer and no talking until the imam has finished."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains Ayyub bin Nahik, who is matruk (abandoned); a group declared him da'if (weak). Ibn Hibban mentioned him in al-Thiqat and said that he makes mistakes.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 3120
Sayyiduna Sulayk (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "When a person comes while the imam is delivering the sermon, he should pray two short rak'ahs."
Ahmad and al-Tabarani in al-Mu'jam al-Kabir recorded it, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 3121
Hadith Gradingمحدثین:إسنادہ صحیح۔
Hadith Takhrij«مسند احمد بن حنبل مسند جابر بن عبد الله رضى الله عنه 14914 ، سنن الدارقطنى اول كتاب الجمعة باب فى الركعتين إذا جاء الرجل والإمام يخطب . 1401 ، أخرجه مسند أحمد برقم: 14759، وأخرجه المعجم الكبير للطبراني برقم: 6711»
Sayyiduna Jabir narrates: Sayyiduna al-Nu'man bin Qawqal entered (the mosque on Friday) while the Prophet (peace and blessings be upon him) was delivering the Friday sermon. The Prophet (peace and blessings be upon him) said to him: "Pray two rak'ahs and keep them short. When any of you comes on Friday while the imam is delivering the sermon, he should pray two rak'ahs and keep them short." (Allamah al-Haythami says:) I say: In the Sahih, Sayyiduna al-Nu'man bin Qawqal is not mentioned in this hadith.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 3122