So Constantine and the council who decided which of the writings done by different men over a thousand years were told by God which to include in it and which to destroy? Many of the old testament books were written hundreds of years after the fact, from stories handed down verbally from generation to generation. Don’t get me wrong - it’s not that I don’t believe in God, but if you ask me if man will change his words to suit their own ends then I will say yes.
Look to the works of John Taylor and his alteration of the King James Bible as a single case in point, there have been many others through time also of course.
Constantine and anybody else involved are an invention of God. If you accept the Truth of Almighty God's existence, that is if you believe in God, then you MUST accept that the words he handed down to us are PRECISELY accurate. Otherwise your god is a bungler, botch artist, clown, farcial ass, take your pick. If you DON'T happen to accept that there is an almighty God then obviously men composed the Bible but in that case who the the hell even cares?
But One who not only can see across time but also INVENTED it, One who knew your name and the number of hairs on your head all the way back at the dawn of Time is not bloody likely to feckup the words handed down. Frankly, if you were to task me with separating the night from the day and the sea from the firmament verses, say, getting the right lingo into a book I'd much rather take the latter assignment. One who could do the former isn't going to stumble much when it comes to accomplishing the latter