Answer:

The Naat “Sona Aaya” mentioned in the question, this Naat has been recited upon a style of a musical instrument and the scholars are in harmony that it is forbidden to recite in such manner Naat and so forth. The recitation of Quran, Naat and so on, along with the daf² or sarangi³, is written by the scholars as gravely forbidden [haram]. However, Mulla Ali Qari wrote even that it is disbelief [kufr], saying, “The one who recited the Quran on a daf and flute is an unbeliever [kafir]. And I would say that closer to this is also the judgment for those who do Allah’s meditation and the Naat of Mustafa, upon whom be peace, together with the daf and the flute.”

[Sharh al-Fiqh al-Akbar: Fasl fi’l-Qiraat wa’l-Salaat: p. 250]

 

Even though this Naat is not recited upon the sound of a daf or sarangi, but by listening, it gives a feeling that a musical instrument was used. The scholars have therefore stated that this is also forbidden [haram]. Huzur Taj al-Shariah Mufti Akhtar Raza Khan al-Azhari (may we be enveloped in his secret) said in one of his fatwa about the judgement of reciting Naat upon the style of a musical instrument,

“Today, a certain type of meditation [zikr] is generalised, with a certain sound similar to the daf that can be heard from the throat. Rather, it is even said by those who say that the meditation is done as such whilst the microphone is between the two lips or very close to it, producing a sound that is comparable to a flute. Many cassettes have been listened to and a similar daf sound can be clearly heard. These people formally produce such sounds that resemble a musical instrument and are similar to the daf. If this is intentional then this is boasting, which is absolutely forbidden [haram], and if such a sound came out unintentionally, then that aspect is like entertainment, which should also be avoided.” [Fatawa Nurani: p. 8]  

 

And this Naat has not been written, nor recited by any scholar, nor is it allowed according to the scholars to recite in such a way. And this is the reality that such ways of reciting Naat have been initiated by the individuals of Dawate Islami, which is absolutely against the Islamic law.

 

But the said curse in the question, if Zayd actually said that and the questioner is true in his own assertion, the Islamic law does not permit Zayd to curse as such to the people of Dawate Islami. Because cursing a Muslim is transgressing and sinful. The Messenger of Allah, upon whom be peace, said, “It is transgression to curse a Muslim.” [Sahih al-Bukhari: 7076]

 

Therefore, it is incumbent upon Zayd to repent [tawba] and not let such inappropriate words get on his tongue in the future. And if Zayd does not repent, then the Islamic law does not permit to follow him in prayer [imamat].