Do you not know?
Have you not heard?
The LORD is the everlasting God,
the Creator of the ends of the earth.
He will not grow tired or weary,
and his understanding no one can fathom.
He gives strength to the weary
and increases the power of the weak.
Even youths grow tired and weary,
and young men stumble and fall;
but those who hope in the LORD
will renew their strength.
They will soar on wings like eagles;
they will run and not grow weary,
they will walk and not be faint.

So do not fear, for I am with you;
do not be dismayed, for I am your God.
I will strengthen you and help you;
I will uphold you with my righteous right hand.

"All who rage against you
will surely be ashamed and disgraced;
those who oppose you
will be as nothing and perish.

Though you search for your enemies,
you will not find them.
Those who wage war against you
will be as nothing at all.

For I am the LORD your God
who takes hold of your right hand
and says to you, Do not fear;
I will help you.

-Isaiah 40:28-31; 41:10-13