We are created and saved to glorify God so the church is to be glorious which applies to the individual “local” church and the church universally as well.
What makes the church glorious? Certainly we aren’t glorious as sinful men therefore it stands to reason that He who is glorious (Christ our Head) makes the body of believers a glorious church. There is an attribute that makes the church glorious and that is known as “harmony.”
Sadly, we have quite a bit of disharmony within “the church,” and this disharmony/disunity detracts from the luminosity of that quality of being “glorious.” The Apostle Paul gives this entreaty in Ephesians 4:2,3 – “with all lowliness and meekness, with long suffering, forbearing one another in love; endeavoring to keep the unity of the Spirit in the bond of peace.”
Also consider 1st Corinthians 1:10 – “Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment.”