For the mind and the soul, as well as for the body, it is God’s law that strength is acquired by effort. In harmony with this law, God has provided in His Word the means for mental and spiritual development. TEd 73.1
The Bible contains all the principles that human beings need to understand in order to be fitted both for this life and for the life to come. And these principles may be understood by all. No one with a spirit to appreciate its teaching can read a single passage from the Bible without gaining some helpful thought. But the most valuable teaching of the Bible is not obtained by occasional or disconnected study. Its great system of truth cannot be discerned by the hasty or careless reader. Many of its treasures lie far beneath the surface, and can be obtained only by diligent research and continuous effort. TEd 73.2
The truths that go to make up the great whole must be searched out and gathered up, “here a little, there a little.” Isaiah 28:10. When thus searched out and brought together, they will be found to be perfectly fitted to one another. Each Gospel is a supplement to the others, every prophecy an explanation of another, every truth a development of some other truth. Every principle in the Word of God has its place, every fact its bearing. And the complete structure, in design and execution, bears testimony to its Author. Only the mind of the Infinite could conceive or fashion such a structure. TEd 73.3
In searching out the various parts and studying their relationship, the highest faculties of the human mind are called into intense activity. No one can engage in such study without developing mental power. TEd 74.1