What is meant by the nullification of deeds in the noble verse: "lest your deeds should be nullified while you perceive not" (Al-Hujurat: 2), and does their nullification imply disbelief?

Listening to the call of the muezzin (adhan (definition)), or the call to commence prayer (iqama) by the one making it, or the recitation of an imam whom you are not following in prayer, is not obligatory. It is also not forbidden to speak during the adhan, iqama, or the recitation of an imam whom you are not following, and doing so does not nullify one's deeds. Following the muezzin is recommended, and listening to the Quran is permissible, but neither is obligatory.

Listening attentively is obligatory for a congregant to the imam's recitation, and for the Friday sermon. The general consensus of the early Muslims (Salaf) interpreted the verse: "And when the Quran is recited, listen to it and pay attention that you may receive mercy" (Quran 7:204) as referring to prayer and the sermon.

The noble verse: "O you who have believed, do not raise your voices above the voice of the Prophet or be loud to him in speech like the loudness of some of you to others, lest your deeds become worthless while you perceive not" (Quran 49:2) is specific to the Companions in their addressing the Prophet, peace and blessings of Allah be upon him, out of respect for him. The nullification of deeds in this context means that this sin (angering the Messenger by raising one's voice in his presence) invalidates good deeds, just as sins invalidate good deeds.