Just a note that the evidences for the heavenly witnesses is not the Greek Majority - Minority issue. This issue is a main part of the discussion on the Mark ending, Pericope Adulterae,
1 Timothy 3:16,
John 1:18 and 1,000 other verses where the corruption modern versions are far inferior to the Authorized Version, often with piddle omission corruptions.
On the heavenly witnesses, the evidence is much more from the Latin side, and came over from the Greek in the first centuries. This is much more like
Acts 8:37, which has light Greek ms. support
The heavenly witnesses has incredible early church writings support, Ante-Nicene like Tertullian followed by Cyprian, also Jerome in the Vulgate Prologue and a Carthage of Council in the 400s where hundreds affirmed the verse in their Bible contra the Arians under Huneric.
The solecism in the short Greek text, the Johannine beautiful consistency and style, all the Latin evidences, and more .. lots of this should be on the thread above.
Many learned scholars see this verse as actually having been difficult for the Trinitarian side in the Sabellian controversies.
Steven