We know the Bible is God’s Word because only God could create it.
Christadelphians: please feel free to keep the ball rolling.
There is a glory to selflessness which every Christian should rightly be captivated by - that soul-gripping conviction that "He must increase, I must decrease," (John 3:30).
The Trinity is part of God’s special revelation to us, and so we should strive to understand it, in so far as our creaturely minds can.
If we refuse God thankfulness, by neglecting, forsaking, or resenting our fellow believers, then we refuse Him his due glory.