Is it permissible to invoke Allah's peace and blessings upon the Prophet (peace be upon him) directly after Adhan (call to Prayer)?
Yes, it is permissible to invoke Allah's peace and blessings upon the Prophet (peace be upon him) after the Adhan directly. It is
(may Allah be merciful to him) on the authority of
`Abdullah ibn `Amr ibn Al-`As (may Allah be pleased with him) (Part No. 6; Page No. 86) that the Messenger (peace be upon him) said,
When you hear the Mu'adhin, repeat what he says, then send blessings on me, for whoever sends blessings on me, Allah will return it to him tenfold. Ask Allah to grant me Al-Wasilah, which is a high rank in Paradise, fitting for only one of Allah's servants and I hope that I will be that servant. Whoever asks Al-Wasilah for me, it becomes incumbent upon me to intercede for them.
This can be done in a low voice only heard to those close to him. However, it is impermissible for a Mu'adhin to invoke Allah's peace and blessing upon the Prophet loudly after Adhan. This is a baseless religious innovation.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.