Ignorance is still a form of thought. You still have the thought of “no thought” even though you do not have wandering thoughts. “Free of thoughts” means “no wandering thoughts.” In Mahayana Buddhism, it is referred to as “having correct thought.” But if you still have the discrimination of “correct thought” and are still attached to “correct thought,” then the “correct thought” becomes a wandering thought. This is not easy to understand.
What exactly is no wandering thoughts? What is correct thought? Having no wandering thoughts is being free of all wandering thoughts, all discriminations, and all attachments. Correct thought is a clear and correct understanding of all principles and matters, causes and results, and the noumenon of anything and its phenomenal expressions. Therefore, in correct thought, there is wisdom, and there are virtues and capabilities, and auspicious marks. In correct thought, there are no wandering thoughts, discriminations, and attachments.
~ Based on Ven. Master Chin Kung's 2003 lecture series on the Amitabha Sutra