And now, Lord, look upon their threats and grant to your servants to continue to speak your word with all boldness...
Acts 4:29
Speak the truth in boldness and God will carry your words to their intended ears.
OTOH, that's not an excuse to ignore principles of rhetoric and persuasion! "God helps those who help themselves" isn't in the Bible, but it's still Scriptural. For example, "A gentle answer turns away wrath."
And when they had further threatened them, they let them go, finding no way to punish them, because of the people, for all were praising God for what had happened.
Acts 4:21
If you speak the truth boldly and publicly (not rudely!), you might be punished--even killed--for it, but the truth, once commonly known, only becomes louder when it is forcibly silenced. If God has been good to you, don't hide it. Make sure that others know, because their faith might depend on your faithfulness.