If so be thou shalt be able... — The words come with a subtle tone of irony. Persevere in thy enchantments ... perchance thou wilt be able to profit, perchance thou wilt strike terror.
Related Commentaries of Isaiah 47:12
Isaiah 47:12
12 Stand now with thine enchantments, and with the multitude of thy sorceries, wherein thou hast laboured from thy youth; if so be thou shalt be able to profit, if so be thou mayest prevail.