DEUT906 ... the Holy One blessed be He has commanded the king "It shall be with him and he shall study it all the days of his life, so that he learns to fear the Eternal his God" [this verse]. From here you are taught that learning [how to] fear [sin] can only be accomplished through uninterrupted study. Examine the way the verse is worded – "so that he learns to fear" – rather than "so that he fears." This is so, because fear of this kind is not something that is naturally grasped. On the contrary, it is far removed from one ['s grasp], due to the physical nature of the senses, and it can only be acquired through learning. And, "learning to fear" can only be achieved through intense, uninterrupted devotion to [the study of] the Torah and its ways. This means that one should reflect upon and delve into this matter all the time – when at home, went on the road, when lying down, and when arising - until the truthfulness of this matter is established in his mind, namely, the truth that the Divine Presence is everywhere and that we are actually standing before Him every moment and every hour. Then one will truly fear Him. This is what David HaMelech prayed for when he said (Tehillim 86:11): "Teach me, O Eternal, Your way, that I may walk in Your truth; unite my heart to fear Your Name."