There is no phrase like that in the Bible, even though it's true.

The weakest point in the chain is the strongest

You might be thinking of the expression, "A chain is as strong as its weakest link." This means that when the ends of a chain are pulled in opposite directions, there is stress on each link; when the weakest link breaks, the chain breaks.

If you put stress on a chain, it will eventually break at its weakest spot. This usually means one of the links in the chain which has been badly welded or is made of inferior metal. The idea is that if you have a group of people, you must assess their capabilities as a group by the least capable.

A chain is only as strong as it's weakest link.