You should know that all Gospels were written AFTER Paul's letters and every Gospel has been "edited" by unknown hands.
Gospel of John is written in allegorical language and writer on many occasion put his own words in mouth of Jesus.
So do not get Dogmatic on what you read in these Gospels, also use your common sense and it would do you good, to read OT books also.
Learn about how God dealt with different people and nations.
Going to extreme in any thing, is what should be avoided.
Peace ..enjoy your religion