Hebrews 11:1 King James Version
11 Now faith is the substance of things hoped for, the evidence of things not seen.
We are to walk by faith and not by sight. Though we may only see darkness for a long while, God will never leave the side of those who earnestly seek Him.
Our joy comes from the hope that we have in God and His promises (that never fail, and thus can never let us down,) and through this hope we find purpose, and thus a reason to keep fighting the good fight.
God promised Jesus Christ will return again. Christ IS coming soon.