Why does it say "Ki"?
Radak: See what brought them to this Avodah. From serving the stars, they came to serve images. Their Kohanim say that this image was made in place of the sun in its honor, so one who serves it is like one who serves the sun, e.g. the gold image that Nebuchadnetzar made for the sun. They make images also for the other stars. They made these statutes for them, and over the course of many years, the masses came to think that the image itself benefits or harms. This is total folly! The image is wood. It was carved from the forest. A carpenter made it with a plane. It cannot do anything by itself. How can it benefit or harm, like the fools believe?!
Malbim (2): Do not learn the way of the Goyim, to think that serving images will gain you favor in their eyes. Their images are folly!
Why does it say "Etz mi'Ya'ar"?
Malbim: It is not even a special wood. It is plain wood of the forest!
What is "Charash"?
Rashi: It is a craftsman (carpenter).
What is "Ma'atzad"?
Rashi: It is a (carpenter's) plane. Malbim - it is not made via a special Kli!