'Really' in the Bible

Indeed, if you keep the royal law prescribed in the Scripture, Love your neighbor as yourself, you are doing well.

Yet you do not know [the least thing] about what may happen in your life tomorrow. [What is secure in your life?] You are merely a vapor [like a puff of smoke or a wisp of steam from a cooking pot] that is visible for a little while and then vanishes [into thin air].