Is the dome of the mosque an innovation?

Allah has guided us to maintain mosques, both physically by building them and spiritually by worshipping in them. He has forbidden their ornamentation and boasting about them. The Prophet (peace be upon him) said: "I was not commanded to build high mosques." He also said: "Indeed, among the signs of the Hour is that people will boast about mosques." There is no harm in building a dome for a mosque if it is for lighting and ventilation, provided there is caution against extravagance and boasting. However, if its construction is an act of worship or an اعتقاد (belief) that it is a Sunnah, then it is an innovation, for the Prophet (peace be upon him) said: "Whoever introduces into this matter of ours that which is not from it will have it rejected."