1 Corinthians 4:15, Begotten You Through the Gospel
The Apostle Paul spoke with a taint of sadness. Like the natural father whose grown up children who may have benefited in their lifetime from the help and nurture of others who may be friends or close relatives. But the father is the one who has imparted life to them. And the Apostle Paul painstakingly took time over a period of year and six months to teach them the doctrines of life. Having been blessed, it seemed they have forgotten their father.