"The disciples were not to wait for the people to come to them. They were to go to the people, hunting for sinners as a shepherd hunts for lost sheep. Christ opened the world before them as their field of labor. They were to go “into all the world, and preach the gospel to every creature.” Mark 16:15 . It was of the Saviour that they were to preach, of His life of unselfish service, His death of shame, His unparalleled, unchanging love. His name was to be their watchword, their band of union. In His name they were to subdue the strongholds of sin. Faith in His name was to mark them as Christians. 8T 14.4"
"Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:"
The EGW passage directly quotes Mark 16:15 and alludes to the Great Commission, which is also found in Matthew 28:19. The connection is clear and intentional.
"And he said unto them, Go ye into all the world, and preach the gospel to every creature."
Ellen White directly references Mark 16:15 in this passage.