First of all, you need to define more precisely who the "you" is in your OP.
If it refers to the person who is reading your OP, the way that person ought to stand up for the truth will still vary depending up the particular circumstance(s) of that person at the time he/she is reading your OP.
For example, if you're talking about a man who is the head pastor of a local church, his response(s) will be different than that of a mother with very small children tugging at her apron strings for something to eat while at the same time she's putting another load of dirty diapers into the washing machine while she's telling her little 4 YO daughter to hold still while she puts a new Band Aid on her bruised and bleeding knee.
The preacher's response would most likely be to draw up a sermon or two that he'll preach to his congregation challenging his flock to become more actively involved in the political realm so that, for example, they might donate their time and money to help out, say, the downtown Gospel rescue mission or maybe a Christian crisis pregnancy center, etc.
OTOH, that poor mother's response would probably be just to stay at home and doing all she can to influence her young children to stop being angry at each other and learn to express their love for their brothers or sisters instead of constantly fighting with each other, or maybe start something like a backyard Bible club where other children are invited to share some snacks while she leads them in some childrens' praise choruses and reads to them stories from the Bible such as young David confronting Goliath and telling those kids that they can be "little Davids too" if they truly depend on Jesus to help them to fight the forces of Satan in their own young lives.
Two people in two different circumstances responding in two very different ways to two different sets of people, but both are doing what they firmly believe are the ways that God is calling them to stand up for the truth.
--------------------------------------------------------------
BTW, did you happen to notice any false teachers in attendance at Bro. Jeremiah's service? If you did, did you do anything personally to confront them with the truths of God's Word?