It seems to me that this "manner of spirit" that Jesus rebuked in James and John may be the same "spirit" which teaches that God will eternally punish in hell those who do not join a Christian church. The Bible tells us who is behind that teaching...
"...Satan himself transforms himself into an angel of light. Therefore it is no great thing if his ministers also transform themselves into ministers of righteousness...." (2 Corinthians 11:13-15)
God is our Savior and Jesus is the Savior of the world. When we believe this God adds us to the body of Christ and eventually all will come to this knowledge and be placed in the body of Christ.
"God has placed the members, each one of them, in the body, just as He desired...this is good and acceptable in the sight of God our Savior, who desires all people to be saved and to come to the knowledge of the truth." (1 Corinthians 12:18; 1 Timothy 2:3-4)
"Furthermore, we have seen with our own eyes and now testify that the Father sent His Son to be the Savior of the world." (1 John 4:14)
God is not keeping track of the sins of the world thank goodness. His Son Jesus atoned for all of them. This is the good news we should tell people.
“He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world....God was reconciling the world to Himself in Christ, not counting people’s sins against them. And He has committed to us the message of reconciliation… God made Him who had no sin to be sin for us, so that we might become the righteousness of God.” (1 John 2:2; 2 Corinthians 5:19-21)
God is not keeping track of the sins of the world thank goodness. His Son Jesus atoned for all of them. This is the good news we should tell people.
“He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world....God was reconciling the world to Himself in Christ, not counting people’s sins against them. And He has committed to us the message of reconciliation… God made Him who had no sin to be sin for us, so that we might become the righteousness of God.” (1 John 2:2; 2 Corinthians 5:19-21)
"But reject irreverent, silly myths. Instead, train yourself for godliness...godliness is valuable in every way, holding promise for the present life and for the one to come. This is a trustworthy saying, worthy of full acceptance. To this end we labor and strive, because we have set our hope on the living God, who is the Savior of everyone, and especially of those who believe. Command and teach these things." (1 Timothy 4:7-11)