God appears to put a high value on weakness, and on the weak (1 Cor 1:27; 2 Cor 12:9-10). In order to understand why / how this is so, we must first have a clear understanding of the word.
According to a dictionary, WEAKNESS is "A part of your emotional / physical / intellectual makeup that appears in the natural to hinder you from accomplishing a given task." In this context, weakness is not the same as sin -- this understanding is critical, although sometimes we use the words almost as synonyms. But to God sin and weakness are almost antonyms -- He hates sin, but He loves weakness. Why would God feel this way about my weakness -- I certainly don't!!
A weakness can be a stronghold for the enemy, but only if you are ashamed of it, you hide it, or deny it -- in some way keep it to yourself. An acknowledged weakness that is brought to the Lord can not be a stronghold -- If you are not holding on to something, there is nothing for the enemy to hold on to, either.
The presence of God is a safe place to be vulnerable, and a safe place to acknowledge weakness -- so He can turn that to a strength.