And David was greatly distressed; for the people spake of stoning him, because the soul of all the people was grieved, every man for his sons and daughters: but David encouraged himself in the LORD his God. 1 Samuel 30:6
The ability to encourge yourself when those around you are dicouraged is an essential attribute of leadership. In our most deperate times, the ability to summon strength through encouraging yourself in the Lord is the greatest act of leadership. It shows that one knows where his help comes from and he believes that just as God has brought him out before, he will surely do it again. David is a good example of that!
Note: Feeling weak doesn't make you a weak person; it's your lack of effort to seek God during your time of weakness that makes you weak.