The words we choose are always important, but especially when we gather to worship. Sam Storms explains how poor word choices can lead to insulting God:
Little words can mean a lot. They can make the difference between good and evil, between heaven and hell. In this case, a right understanding of a single word is the only thing that prevents an act of worship from degenerating into a colossal insult to God. It’s the word “for.”
It gets especially tricky with words that can carry multiple meanings, as Sam explains.