One of the biggest obstacles to unity in the Church is the fact that many in the Church have a different approach to unity. For some, it's ok to differ as long as we don't bicker. For others, we must bicker, because we are supposed to be of one mind. The result of the latter, tragically, is often to cast off wheat and chaff alike.
But I would argue the result of the former, while considerably less severe than dividing the Church by casting out genuine believers as though they were servants of Satan, is still quite spiritually damaging. It is true that we must endeavor to keep the unity of the Spirit and the bond of peace (Ephesians 4:3), but it is also true that we must seek to speak the same thing, avoiding divisions, but being perfectly joined together in the same mind and the same judgement (1 Corinthians 1:10).
Furthermore, consider the very purpose of Scripture: "All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work." (2 Timothy 3:16-17).
Now, if this is the purpose of Scripture, what does that say about those who are content to be incomplete? "Just focus on the Gospel." Does the Bible just focus on the Gospel? "Let's agree to disagree." Does Scripture disagree? "To each his own." Then why read His own?
Obviously, we are all weak in the flesh. We are supposed to aim for unity, but we will always find carnality. Nevertheless, God did not give us His perfect word so we may lay it aside and continue in our own ways. Nor did He inspire it so that we may draw our own conclusions. Rather, we are supposed to draw His conclusions.
And frankly, God is not an Earthly teacher. He's not going to include random tidbits that won't appear on the final exam. Every word of Scripture is worth treasuring in our hearts. If we can learn it, we should. If we can understand it, we must. If we can apply it, we will be judged for our failure to do so. So why do we so consistently shrug off this duty? Just because it's not a Gospel issue? Error won't take us to Hell, so we reason that the truth will not benefit us even on the Earth?
We do not even apply this folly! Those who most often excuse their error in this way will continue to insist on it. They agree to disagree only because they seek to disagree. In other words, they don't want you insisting on your opinions because they insist on theirs.
Is it not wiser for iron to sharpen iron? If we disagree, at least one of us is wrong. And what benefit does that bring? Of course, all things work together for the good for those who love the Lord and are called according to His purpose. Thus, God is quite capable of bringing good things from bad things. But why would we choose the bad things? Just because you won't fail a test if you get a particular question wrong doesn't mean you want to put the wrong answer. Go for full marks! You might not get full marks, but why wouldn't you try?
Ultimately, we are fallible beings. As Mike Winger once said, "Scripture is sufficient, that does not mean that I am sufficient". Nevertheless, there is a huge difference between being errant and being foolish. When we use our shortcomings as an excuse for our shortcomings, all we end up doing is damaging our faith. Let us therefore pursue the truth, mining every single nugget of gold, silver, and precious stones we can. If we leave even one behind, we only rob ourselves.