I am of the opinion that information that helps us understand Isaiah is always a good thing. Pillai's explanation of customs is so helpful here. It adds another layer of understanding that enhances Isaiah's warning to trust in God's light rather than the arm of flesh if we don't want want to "lie down in sorrow" at the end of our days.
Behold, all ye that kindle a fire, that compass [yourselves] about with sparks: walk in the light of your fire, and in the sparks [that] ye have kindled. This shall ye have of mine hand; ye shall lie down in sorrow. Isaiah 50:11
" In the East, the farmers get up early and build a fire to warm themselves. When they are ready to start to the fields, they take a heavy rope and put the end of it into the fire. They blow on this burning rope to send out sparks ahead of themselves to light the way so that they will not step on a scorpion or snake with their bare feet.
The verse is saying, we must have the light of God to illuminate the way; we cannot walk safely through the sparks that we have kindled ourselves. We will not stumble in God’s light."
Pillai, K.C. Light through an Eastern Window, pg. 117
If you would like an excellent reference book that illustrates many of the verses in Isaiah with beautiful photographs, get Visualizing Isaiah by Don Parry, It's a favorite of mine and perfect for teaching young people.