Paul encourages the Philippian Christians to be content in their circumstances - Philippians 4:10-13
I rejoiced greatly in the Lord that at last you renewed your concern for me. Indeed, you were concerned, but you had no opportunity to show it. I am not saying this because I am in need, for I have learned to be content whatever the circumstances. I know what it is to be in need, and I know what it is to have plenty. I have learned the secret of being content in any and every situation, whether well fed or hungry, whether living in plenty or in want. I can do all this through him who gives me strength.
Paul's certainty was in God. Nothing can separate us from God's love.