One of the most inspiring verses in the Quran, and one that always enters my mind whenever my brain tells me "it's impossible!" is Prophet Ya'qoob's words to his sons after they despaired of rescuing their captured brother:
Do not despair of God's mercy, for indeed none despair of God's mercy other than disbelieving people. [12:87]
This verse has taught me to never lose hope. God has the power to get us out of any trouble we could possibly get into. All that's needed is to stay steadfast on our path, to always stay close to God, for as He says:
And whoever has taqwa (stays constantly mindful of God), God will create for him a way out, and He will provide for him from sources he never expected. And whoever puts all his reliance on God, then God is all that he needs. [65:2,3]
What a wonderful promise to the believers!