The written word, specifically.
After becoming embroiled in a discussion I hadn't planned on entering on Facebook this morning, I am yet again reminded of the power of words. The scenario: a person passes along an email they received that uses a Bible passage to "prove" that liberals are fools and conservatives are wise people. The email is passed on with only the message "I felt compelled to share this." Naturally this ruffled feathers between the poster and their liberal friends, myself among them. What stands out the most to me about this is that the words used for this shared email were hurtful, and done so in a truly passive aggressive manner designed to be hurtful. And even had the audacity to try and imply that God approved of such hurtfulness, because it's in the Bible, after all... The person who posted this by not stating their outrage or disbelief of the email is by default agreeing with it even if they later claim they don't. This is why we must choose our words so carefully. Particularly in a non-verbal setting when we can't see body language, or hear tone of voice.
I wish people could understand this before they write things or share other people's things that they wrote. I think some people have a natural way with words, and some people do not. This isn't to say that they cannot learn and improve with time, but they must first see that this is perhaps not a gift given to them and that they will have to always think harder and first before writing or sharing anything, particularly in an online situation. Thinking before writing is always a good rule of thumb.
What I also wish that people who claim to be Christians and people who wish to bring people together in Christ, could realize that they can do so much damage with their words. As a person who is liberal in politics and her spiritual stance, hearing insulting words passed on as though they come from God Himself certainly doesn't make me want to visit a church again any time soon. Not if I'll be surrounded by haters like that who judge me silently, or not-so silently, for my beliefs that clearly differ from theirs. So, by passing along a message without really thinking about the implications and consequences, this person has actually managed to anger and continue to distance from God, the very people they wish to win over for God. And this is why we must all choose and use our words so carefully, especially online. You never know who else will be reading them and what message you might be passing on to them.