I'm no 'deep theological thinker' (which I think sometimes is a just a euphemism for someone who uses $100 words to promote two bob heresies), but it seems to me that Biblical unity is an exceedingly simple concept made complicated by many.
Unity, biblical unity ,that is the unity of the Spirit can only exist where the Holy Spirit is ,and the Spirit of God will always promote ,exalt and glorify the Lord Jesus Christ; His person, His work ,His ways and His word.
A crucial element of true scriptural unity is division. Jesus said "do not think I came to bring peace but a sword " He said that we would have enemies and at times they would even be members of our own household. The ecumenicists , the pragmatists, the emergents and the institutionalized religionists need to remember that unity REQUIRES separation: a separation from that which is not of God to that which is.
Every person born again by the Spirit of God ,through the word of God unto the Son of God for the glory of God ,is already unified with all others who have experienced this grace and we are already family.Church structures,religious activities and nice sounding words do not build unity .
See , unity is not uniformity as though if we could just act the same,dress the same, look the same ,talk the same we could please God ...but God created diversity and we are meant to treasure and value the differences that all His blood bought children demonstrate and like a multifaceted diamond, His true church reflects some aspect of his glory ,for His glory .
And unity is not the same as union. Organizational bridge -building is a futile human endeavour that ignores and demotes God and in His place puts an institutional idol. The scripture says how can they prepare if the trumpet does not sound a clear call . The muted ,muffled message of ecumenicalism is no way to preach the only and eternal gospel.
The truth is the false gospel of worldly unity far too often usurps the Lordship of Christ Jesus and ushers in a doomed kingdom of backslapping ,baby kissing religious politicians but as always these weak kneed non-combatants will reject ,sideline and slander the robust love and the united prophetic voice of the true church of God.