"Dear brother, be warned. Be true to the light which shines upon your pathway. Said Paul: “I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway.” 4T 371.1"
"But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway."
The EGW passage directly quotes 1 Corinthians 9:27, making it a clear and intentional explicit allusion.