There is no harm in chanting Islamic songs as long as nothing prohibited accompanies them such as prohibited musical instruments, and no confusion happens to those praying in the mosque, and there is no imitation of immoral persons when delivering such songs.
In this regard, the fatwas of Islamic Web state the following: The most correct view in this regard is that it is permissible to recite poetry in the mosque provided that this poetry is of the kind that praises Islamic teachings, urges adhering to jihad and morality, and suchlike good purposes. In this connection, Imams Al-Bukhari and Muslim reported that `Umar (may Allah be pleased with him) passed by Hassan ibn Thabit (the poet) while he was reciting poetry in the mosque. (Disapproving of that,) `Umar looked at Hassan who said, “I used to recite poetry in it (the mosque) in the presence of one who is better than you (that is, the Prophet).” There are many other hadiths telling that the Prophet’s Companions recited poetry in the presence of the Prophet (peace and blessings be upon him).
On the other hand, reciting poetry should be forbidden in the mosque if it leads to noise and raised voice, for this is forbidden in Islam. `Abdullah ibn Mas`ud (may Allah be pleased with him) narrated that Allah’s Messenger (peace and blessings be upon him) said when straightening the rows in Prayer, “Let men of understanding and discretion be near me, then those who are next to them (saying it thrice); and beware of the tumult of the markets.” Commenting on the hadith, Imam An-Nawawi said that raised voice and noise are included in what is meant by the phrase “the tumult of the markets,” which is also applicable in case of singing jointly.
As for the judgment of Islamic songs, they are deemed lawful according to the preponderant opinion as long as they do not include prohibited meanings or words, or are accompanied by prohibited musical instruments, or are performed in a way of imitation of wicked and immoral people.