Contradiction with Matthew 28:19
This verse commands believers to make disciples of all nations, which may seem contrary to 2 John 1:13 if interpreted as private greetings.
Matthew 28:19: Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: [teach...: or, make disciples, or, Christians of all nations]
Contradiction with Galatians 3:28
This verse speaks of unity among believers regardless of status, while 2 John 1:13 could be seen as maintaining distinctions in greetings.
Galatians 3:28: There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.
Contradiction with Acts 10:34-35
This verse highlights God's impartiality, in contrast with 2 John 1:13 potentially implying selectivity in greetings.
Acts 10:34-35: Then Peter opened [his] mouth, and said, Of a truth I perceive that God is no respecter of persons: