Philippians 4:10-13; Paul gives us one of The Bible's most quoted verses in verse 13: "I can do all things through him who strengthens me." Equally important is the verse before: "for I have learned in whatever situation I am to be content. I know how to be brought low, and I know how to abound. In any and every circumstance, for I have learned in whatever situation I am to be content. I know how to be brought low, and I know how to abound. In any and every circumstance, I have learned the secret of facing plenty and hunger, abundance and need."
Paul says he's learned that, "I am to be content . . ." Notice he doesn't claim to have achieved perfection; but flowing from of his his identity in Christ; he understands how or what he is to be, which is content; in all seasons of life. Paul could only do this (we can only do this) through our union with Christ. The only way to be able to "do all things" is to be devoted to God, and seek to please Him with our endeavors and "through" Jesus' strength and power we can and will do all things God has for us to do.