The Lord will have his way.  The scriptures are clear that He one day will set all things right for eternity.  In the interim, while we still reside in this fallen world, God also will move justly in response to our prayers.  We do not always see the result of our requests for God's justice, but we can be sure that He will answer us.  Let us not lose heart but have the faith always to contend for justice with expectation.