Fight the good fight
idiom : to try very hard to do what is right(Merriam-webster Dictionaries)
These words mean to face the betrayal, slander, lies, and violence of others, to have the mental strength to get back up even when knocked down, to never lose hope, and to continue fighting for justice.
And I think they encourage us to never give up even in the face of failure, defeat, and humiliation, but to walk in trust in Jesus.

Fight the good fight of faith, lay hold on eternal life, (1 Timothy 6:12 NKJ)
I have fought the good fight, I have finished the race, I have kept the faith. (2 Timothy 4:7 NKJ)
No temptation has overtaken you except such as is common to man; but God is faithful, who will not allow you to be tempted beyond what you are able, but with the temptation will also make the way of escape, that you may be able to bear it. (1 Corinthians 10:13 NKJ)
God is our refuge and strength, A very present help in trouble. ( Psalm 46:1 NKJ)