For he will give his angels charge of you to guard you in all your ways. On their hands they will bear you up, lest you dash your foot against a stone. (Psalms 91:11-12)
(Actually you can use the whole Psalms 91)
I cannot tell you a particular quotation, but the story of Joseph, son of Israel, has always been my support in the hard times. Please read starting from Genesis 37. It is the story of the Lord preparing Joseph for greatness.