The "undesigned coincidences" of the Gospels

And Jesus said unto them, 

See ye not all these things? 

Matthew 24:2

"The four different gospel accounts have ‘undesigned coincidences’ that reinforce each other’s authenticity, including, e.g., in regard to the feeding of the 5,000. 

Mark says the grass was green (6:39) and that Jesus was escaping the crowds (6:31). 

Q: Why green grass and crowds? 

John writing decades later says it was near Passover (John 6:4), just the time of year where there would be lush green grass and crowds. John also records that Jesus, testing Philip, asked him where they might get food (6:5,6,7). 

Q: Why him? 

John had already said Philip was from Bethsaida (1:44). Luke, not John or Mark, supplies the answer: the feeding was near Bethsaida (Luke 9:10). 

Thus, the combination of these gospels makes sense of Jesus’ choice of Philip: someone with local knowledge. 

In such ways the gospel writers inadvertently reinforce the authenticity of each other’s reports." 

CMI