Jude 1:08 In the very same way, these dreamers pollute their own bodies, reject authority and slander celestial beings. 9But even the archangel Michael, when he was disputing with the devil about the body of Moses, did not dare to bring a slanderous accusation against him, but said, "The Lord rebuke you!" 10Yet these men speak abusively against whatever they do not understand; and what things they do understand by instinct, like unreasoning animals—these are the very things that destroy them.
So, if Michael, one of the Lord's angels takes care to not speak slander against the devil himself, then God must take these words of ours seriously. We are not the only ones He holds up to this standard of speaking what is good.
I like what verse 10 talks about, men who don't understand something speak abusively against it. Wow! How cruel! However, I know what this feels like, I was just thinking about when I was younger, and how to kids got me by myself on a walk from one place to the other and called me stupid to my face (they were walking backwards looking at me) for about ten minutes straight. I don't even know why they did this, but it was abuse according to Jude 1:10. Do you know that made me feel less confidente in my own intelligence? I haven't been able to recover until now and that is saying something.
So, when your thinking about slandering something just because you don't understand it, remember in God's eyes, your being abusive.
Take your words serious, and judge them before your let them come out of your mouth. It takes a concious effort, and believe me, I know, it's hard. However, when I go before God, I don't want to be ashamed of what I've said. I want my book of rememberance to be filled with accounts of showing God's love, not abusing someone or something.