"Harmonious Development No one branch of study should receive special attention to the neglect of others equally important. Some teachers devote much time to a favorite branch, drilling students upon every point, and praising them for their progress, while in other essential studies these students may be deficient. Such instructors are doing their pupils a great wrong. They are depriving them of that harmonious development of the mental powers which they should have, as well as of knowledge which they sorely need. CT 232"
"For the body is not one member, but many."
Both passages emphasize the importance of balanced development and the interconnectedness of different parts. EGW applies this to studies, while 1 Corinthians 12:14 applies it to the body of Christ.
"In these matters, teachers are too often controlled by ambitious and selfish motives. While they labor with no higher object, they cannot inspire their pupils with noble desires or purposes. The keen, active minds of the youth are quick to detect every defect of character, and they will copy defects far more readily than they will the graces of the Holy Spirit. CT 232.2"
"Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit."
Both passages discuss the influence of character, good or bad, on others. The EGW passage focuses on teachers and students, while the Bible verse uses the analogy of trees and fruit. The connection is thematic rather than a direct principle.
"Many thus build barriers between themselves and Jesus, so that His love cannot flow into their hearts, and then they complain that they do not see the Sun of Righteousness. Let them forget self and live for Jesus, and the light of heaven will bring gladness to their souls. CT 232.3"
"But unto you that fear my name shall the Sun of righteousness arise with healing in his wings; and ye shall go forth, and grow up as calves of the stall."
The EGW passage explicitly uses the phrase 'Sun of Righteousness,' which is a direct reference to Malachi 4:2. The context of light and healing further strengthens the connection.