The forms of unbelief are varied, for Satan watches every opportunity to crowd in some of his attributes. There is in the natural heart a tendency to be exalted or puffed up if success attends the efforts put forth. But self-exaltation can find no place in the work of God. Whatever your intelligence, however earnestly and zealously you may labor, unless you put away your own tendencies to pride, and submit to be guided by the Spirit of God, you will be on losing ground.
Spiritual death in the soul is evidenced by spiritual pride and a crippled experience; those who have such an experience seldom make straight paths for their feet. If pride is nourished, the very qualities of the mind which grace, if received, would make a blessing, become contaminated. The very victories which would have been a savor of life unto life, if the glory had been given to God, become tarnished by self-glory. These may seem to be little things, unworthy of notice, but the seed thus scattered brings forth a sure harvest. It is these little sins, so common that they are often unnoticed, that Satan uses in his service.
– S.D.A. Bible Commentary, Vol 6, pg. 1080