The word "prevail" is unquestionably optimistic. A victory is implied. It implies to triumph in the end, to be victorious. This is not a matter of stubbornly pressing on to the very end. Ultimately, this is about trusting God to guide our efforts. To joy. That's how you win. God will ultimately win. He's come up with a brilliant strategy. God has a good plan for everyone's happiness. That's why all of us here on Earth are here: to absorb knowledge, develop personally, and enjoy life to the fullest. God provides the opportunities for us to grow, and in that progress is deeper understanding and peace, even if we know that our lives will not be devoid of struggles, low times, pain, or frustration. If we let it, each trial can shape us into the people God wants us to be if we give up and allow God to accomplish His thing through us.