I took metal shop in high school to learn how to weld. My test was when the instructor came by with a hammer to see if he could break apart the pieces of metal that were welded together. Thinking that if I added more welds to the two pieces, the instructor would not be able to break apart my weld. I was wrong. A good mentor and friend showed me a few years ago the key to doing a proper weld. If you are taking two flat pieces and wanting to hold them tight with a weld, you need to grind a little off of each piece. It is then that the weld can bond the two at that point. At that point, if done properly, the weld will be stronger than the other parts of the now one piece of metal.
As believers wanting to stand united, we may need to knock off a few of our own thoughts or ways so we can be bonded with other believers.
1 Corinthians 1:10 (NIV)
10 I appeal to you, brothers, in the name of our Lord Jesus Christ, that all of you agree with one another so that there may be no divisions among you and that you may be perfectly united in mind and thought.