• The Laws of Logic Hold Universally
• Christianity's distinctive, characteristic beliefs

This has been flagged as an appeal to authority. Before removing this flag, ensure the reasoning is based on the evidence the authority had, not the authority itself.

• The ecumenical councils held the position that the Son has always been fully God
• The positions of the ecumenical councils have stood up to scrutiny for 2,000 years
• If the positions have stood up to scrutiny for 2,000 years, they are true
• If the above is true, the Son has always been fully God

∴ the Son has always been fully God

Niceno-Constantinopolitan Creed

• Jesus could not fully save the elect from their sins if He had not always been fully God
• Jesus fully saved the elect from their sins
• If the above is true, the Son has always been fully God

∴ the Son has always been fully God

Athanasius

x the Son has always been fully God