People erroneously think that believers are weak when they choose to serve God, rather than pursue their own desires, or the world's pleasures. But it takes a far greater strength to surrender to God's will, rather than to pursue your own. The weakest people of all, are those who live bound to the demands and desires of their own flesh. Think about it: Submission to the flesh is natural, it comes easy. Every baby is born pursuing their own will, and desires. That's how we are born, and that's how many choose to live.
But to overcome the flesh, with all its lust and weaknesses - requires the kind of strength that is unheard of in the world - a strength not born of this world. Only the strongest among us (Christ followers) can kick their flesh to the curb and pursue the requirements of God's kingdom instead of the things that please and promote the flesh.