With regards to the first ʾathān of the Friday prayer, is the ʾathān repeated after the muʾathin?
Shaykh Sāliḥ ibn al-Fawzān:
The [first] ʾathān is Islamically legislated because it is from the sunnah of the Rightly Guided Caliphs. The third Caliph ʿUthmān enjoined it whilst the Rightly Guided Caliph ʿAlī ibn Abī Ṭālib, the Muhājirīn and the Anṣār were present, and they did not prohibit him from it. Except what has been narrated upon Ibn ʿUmar as Ibn Abī Shaybá (d. 235 AH) reports in his lexicon of ḥadīth, that [Ibn ʿUmar] said it is an innovation. Ibn al-Rajab (d. 795 AH) explained when he reported the statement of Ibn ʿUmar, “He intended a good innovation and not an evil innovation..’ just as his father said with regards to the Tarāwīḥ prayer, ‘this is a good innovation..’” meaning it is an innovation in terms of the language and not religiously. 1
1. [TN]: Ibn Rajab said in his explanation of Ṣaḥiḥ al-Bukhārī, “and due to that – the first ʾathān on Friday, ʿUthmān added it because of the people’s need for it. ʿAlī approved of it and the Muslims continued to acting upon it. It has been reported that Ibn ʿUmar said, ‘It is an innovation…’ and he could have intended just as his father intended about the tarāwīḥ in Ramaḍān..” (Fat`ḥ al-Bārī 5/462)
He also said in his explanation of Imām al-Nawāwī’s (d. 676 AH) Forty Narrations, “Another example is the first ʾathān on Friday which ʿUthmān added due to the people’s need. It has been reported that Ibn ʿUmar has said “It is an innovation..” but it is likely that he meant just as his father meant about the tarāwīḥ prayer in Ramaḍān…” He further mentioned “Likewise there is the compilation of the Qurʾān into one book, which Zayd ibn Thābit said to Abū Bakr and ʿUmar , “How can you two do something that the Prophet didn’t do?” then he came to realise the benefit of it and agreed to compile it.”
Ibn Taymiyah (d. 728 AH) said in his al-Majmūʿ, “Whatever was enacted by the Rightly Guided Caliphs is not considered a religious innovation that is prohibited, even though it is called an innovation linguistically for it being introduced as ʿUmar ibn al-Khaṭṭāb said, ‘What a good innovation this is..’” [Majmūʿ al-Fatāwá 21/319]
He then mentioned elsewhere, “Indeed if others were to oppose the Rightly Guided Caliphs, then the statements of Rightly Guided Caliphs will be the preeminent opinion due to the statement of the Prophet, ‘upon you is my Sunnah and the Sunnah of the Rightly Guided Caliphs after me, hold onto it with your molar teeth..’ [Majmūʿ al-Fatāwá 32/347]
It can also be found in his Minḥāj al-Sunnah that he remarked, “….so the answer is, ʿAlī was of those who agreed with [the first ʾathān] during the lifetime of ʿUthmān and after he was murdered. Due to this, when he became a Caliph he did not order with the termination of the first ʾathān to be…” [Minḥāj al-Sunnah 2/290]