"Holy Father, protect them in your name that you have given me, so that they may be one, as we are one." (Jn. 17.11)
This verse gets trotted out every time a Christian thinks upon the unhappy divisions that beset the Church and the mayhem (ranging from snarky to all-out war) which results. One has to ask, "What happened?"
Like Peter, when we pay more attention to the problems that beset us and succumb to fear, we no longer walk with Jesus and begin to sink. (Mt. 14.30)
Our besetting sin is when we take our minds off God, whether to chase some theological rabbit across the meadow and fall into the river, or we do so to focus on the storm around us and fall out of the boat into the sea, when we turn our focus away from God, when we no longer seek God, when we forget the greatest commandments of God, we fall out of that protection, or rather we step out from behind it.
It's a nasty world out there. The sunshine and rainbows are accompanied by hurricanes and earthquakes. If we fail in our focus on God, loving Him AND our neighbour, we will fail in that prayer that we all will be one. The Scriptures are FULL of how love will prevail over all fear, over all sin, over all strife, but also contain dire warnings about what happens when love is abandoned in favour of either self-gratification or worse yet a righteousness devoid of love and mercy. Both these ills tear us away from God and create a host of ills that prevent us from addressing other ills around us, from living the Kingdom of God about us.
Only then can we live up to the expectation held forth by the Gospel.