Again, whence do you draw this principle? Where is this "injunction" which you speak of?The names of the days and months, to me, fall under the category of those things which are common to societies and for the orderly functioning of daily life we must submit to. Unless we have Scriptural injunction otherwise. Here we do: we have two names specifically given to the first day of the week in Scripture. We should use them instead of the clearly pagan "sunday".