Wherefore (as the Holy Ghost saith, To day if ye will hear his voice, Harden not your hearts, as in the provocation, in the day of temptation in the wilderness). Hebrews 3:7, 8
It is not God that blinds the eyes of man or hardens their hearts. He sends them light to correct their errors, and to lead them in safe paths; it is by the rejection of this light that the eyes are blinded and the heart hardened. Often the process is gradual, and almost imperceptible. Light comes to the soul through God's word, through His servants, or by the direct agency of the Holy Spirit; but when one ray of light is disregarded, there is a partial benumbing of the spiritual perceptions, and the second revealing of light is less clearly discerned. So the darkness increases, until it is night in the soul. Thus it had been with these Jewish leaders. They were convinced that a divine power attended Christ, but in order to resist the truth, they attributed the work of the Holy Spirit to Satan. In doing this they deliberately chose deception; they yielded themselves to Satan, and henceforth they were controlled by his power. (The Desire of Ages, 322)
Reflection: If we saw ourselves as servants of God we would be more attentive in making the best choices in this conflict between good and evil. It is often our sinful independence from God that makes us so careless. Conscience is the voice of God, and when resisted, it grieves the Holy Spirit. Many wait for more light while rejecting present light. They wait for better opportunities and neglect present duties. If we are not careful, the light we have will be withdrawn, and we will be left in darkness.