The artisans made the tapestries [for the Tabernacle] out of linen, turquoise wool, purple wool, and scarlet wool.
These four materials allude to the four bases of our emotional relationship with G-d.
Scarlet wool is red, alluding to fire. The fire within our soul is the fiery love of G-d that results from contemplating His infinity. When we realize the extent to which G-d is beyond creation and that He is the true reality, we are overcome with a passionate desire to escape the limitations of the world in order to know Him and to merge with Him.
Turqouise wool is the color of the sky, alluding to our experience of G-d's majesty. In this experience, we also contemplate G-d's infinity, but focus on our own significance in comparison. This fills us with feelings of awe.
Purple wool is a blend of blue and red, of love and awe, alluding to pity, which is compounded of love and anger: love for the ideal, anger over how the ideal goes unfulfilled. Specifically, we pity our Divine soul when we consider its plight, having to live so spiritually distant from its natural home, i.e., in G-d's presence.
Linen is white, alluding to our basic, inherent love of G-d, a feeling that is above and beyond rationality. This love is what makes us capable of self-sacrifice for G-d's honor, since as it expresses our invincible bond with G-d.
From Daily Wisdom