Tefilin:

1. The straps of the tefilin are a protection for faith against the parasitic forces of evil. They protect the mind and the soul, and fresh wisdom and a fresh soul are drawn from the inner light of God's countenance (35:9).
2. A person should constantly search himself to see if he is attached to God. The tefilin are the sign of attachment (38:1).
3. The way to experience the true sanctity of tefilin is by sanctifying and purifying speech, which is achieved by learning Torah even when one is poor or under great pressure. When a person is overwhelmed with darkness and suffering and still makes an effort to study Torah, he elevates the faculty of speech and he will be able to speak to his Maker with strength and fire and pour out his words in truth. He will understand his own insignificance and the utter greatness of the Creator, and he will be filled with shame at the greatness of his sins against the Master and Ruler of the Universe, the Root of all the worlds. His shame will show on his very face, and then he will be worthy of the light of tefilin, which are the sign of attachment to God (Ibid. 2,4,5).
4. Tefilin are the `radiance of God's countenance.' They are the true glory of Israel. The are `life' and `truth,' the source of wealth and all blessings. Abuse of the tefilin brings poverty, contempt and shame and puts one in mortal danger, God forbid (47).
5. The tefilin strengthen the memory -- the awareness that the goal of this world is the World to Come and that one must constantly expand one's intellect so as to understand the messages God sends every day in order to draw men closer to Him (54:3).
6. The more efforts a person makes to break his immoral desires, the more receptive he becomes to the holiness of tefilin. It is those who are truly righteous and God-fearing, the `guardians of the earth' who fulfill the mitzvah of tefilin to perfection. The full force of immoral temptations is unleashed against them with a fury and could even bring them to waste their seed and be stamped with the seal of the forces of the Other Side, God forbid. But they steel themselves against them, totally separating themselves from any such thoughts, and they elevate the seal of the evil husk until it becomes transformed into the seal of holiness -- the tefilin, which embody the radiance of the sparks of wisdom, whereby one knows and acknowledges the Divinity and Kingship of God. The light of the seven faithful shepherds shines, corresponding to the seven heads of the two shins' on the tefilin (one with four heads, the other with three). Thus the significance of the tefilin is that we have to draw down the radiance of God and strive for ever-deeper understanding of Godliness. But there are necessary limits to the human intellect, and these must also be observed. The tefilin are the tikkun for this, enabling us to deepen our understanding while remaining within the bounds of holiness. Even in our striving to draw close to the radiance of Godliness, it is forbidden to go beyond the boundaries and `break through' (cf. Exodus 19:21).