What is the spiritual intellect?

Spirit guides impart the magnetic propensities requisite to our physical vitality. 

The moment incarnation takes place, there is assigned to us a spiritual guardian who holds constant vigilance, many times using means in controlling such material conditions that might retard our progress in future experiences. 

This is in every case a truth many times upon the undeveloped plane when the intellectual forces cannot approach, the conditions are then controlled by undeveloped influences. The higher cannot obtain power immediately, but in after years, through psychical and careful instruction, the influences yield to the higher law—the undeveloped withdrawing, giving conditions to the superior.

In this wise, man is carefully instructed in the natural forces of Nature's laws, developing faculty after faculty, interblending with the more powerful, unfolding the several attributes within the nature of himself. 

Looking up as he does, the unfoldment of the spirit grows in strength and in power, and through constant development interblends with the superior intellects of the spirit spheres.

—B. H. in Spirit