Bible Series part 4

Show Note Correction!  I should have said the council of Chalcedon not Orange!  Just ignore that name when listening. Thank you.

In part 4 we continue looking at intentional errors in the New Testament.  Here we look at the difference between Matthew 24:36 and Mark 13:32.

But as for that day and hour no one knows it - not even the angels in heaven - except the Father alone. -Matthew 24:36
But as for that day or hour no one knows it - neither the angles in heaven, nor the Son - except the Father. -Mark 13:32

Why did someone remove "nor the Son" from Matthew?  When did this happen and why?

 

We also look at the Comma Johanine (1 John 5:7-8).  Does this verse teach us about the Trinity or is this a verse that was added later for Christians to prove the Bible teaches a Trinitarian concept?

For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one. And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one. -1 John 5:7-8 KJV
For there are three that testify, the Spirit and the water and the blood, and these three are in agreement. -1 John 5:7-8 NET

Is there a good reason to change the Word of God for the sake of theological clarity?