What is the significance that silver has a source?
Rashi: This is another support for his claim "b'Tzidkasi Hechezakti" (27:6). Why should I be a Rasha? If it is for silver and gold - they have a source and end! However, "ha'Chochmah me'Ayin Tavo" (20) - this is dearer than all, so I put my heart to learn.
Malbim: Everything scarce and important to people, e.g. copper and iron that are needed for Kelim, or gold and silver, which people store for honor, people searched where they are found. There are many strategies how to find them deep in the land or in mountains.
What is "Yazoku"?
Rashi: They melt it.
Ibn Ezra: This is like Yezakeku (they refine it). He teaches that everything depends on people's Mazal, including places.
Malbim: They separate it from the sand and earth that is mixed with it.
