Sayyiduna Jabir (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "When the iqamah is given for the prayer, the gates of the sky are opened and supplication is answered."
Imam Ahmad recorded it; its chain contains a narrator, Ibn Lahi'ah, about whom there has been criticism.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 1918
Qatadah narrates: When someone came to Sayyiduna Uthman (may Allah be pleased with him) to call him to the prayer, he would say: "Welcome to those who speak with justice, and welcome to the prayer, and greetings."
Imam al-Tabarani recorded it in al-Mu'jam al-Kabir; the narrator Qatadah did not hear from Sayyiduna Uthman (may Allah be pleased with him).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 1919