It takes strength to do what must be done when the work is unpleasant and uncomfortable.
It takes strength to persist in the face of obstacles, when it would be much easier to simply give up.
It takes strength to be polite to someone when that person has been rude to you.
It takes strength to be truthful when a lie would be more convenient.
It takes strength to build for the future.
It takes strength to resist temptations and distractions.
It takes strength to do what is right.
It takes strength to do all these things. And all the while, these are the very things that build even more strength.
Be truthful, do what you know is right, put forth effort when it is called for, and persist.
The more you do so, the more easily you'll be able to do so.
Exercise your strength, and you'll surely grow stronger, more capable, and successful in each endeavor