Is bible interpretation dangerous blasphemy...i thought it said you cant add to it?

Rapture and Trinity are in there. Not the words, but the meaning is there in Greek words that did not get translated into the words rapture and trinity. It's a matter of translation. Like calling God "Lord." That is nowhere in the original written versions in ancient languages. God's name is Yahweh in the Old Testament. But it is translated "Lord" in our present day Old Testament.