According to this Satan will have his time to rule. But the hope comes in verses 24 and 25. 24 says "his power shall be great-but not by his own power." God has appointed all of this. All is for His glory. 25 is very clear. Satan will be defeated. But clearly it isn't anything we do, but what God does. We should rejoice in his ultimate defeat at the hands of our great King. If we focus on God's ultimate glory, it becomes easier to take the hard things in life, including the things foretold here.

Daniel 8:24-25