Those who think the unessential is essential, and see the essential as unessential; They do not attain the essence, being in the domain of wrong intention.

– DhammaPada Verse 11

And those who know the essential as essential, and the unessential as unessential; They attain the essence, being in the domain of right intention.

– DhammaPada Verse 12

Related Teachings:

Thoughts arise from a cause, not without a cause (SN 14.12) - In this teaching, the Buddha is sharing that as one grows in mindfulness, one is able to have a greater choice in recognizing which thoughts are arising and if they’re in the unwholesome category, then one is able to apply right effort and abandon them.

Developing the mind by classifying thoughts into two categories | Right Intention (MN 19) - The Buddha describes how he cultivated his mind with a careful categorization of thoughts to cultivate and thoughts to eliminate, understanding their relationship and how it inclines the mind’s underlying tendencies.

A Heap of Bones (ITI 24) - The Buddha shares on the incomprehensible nature of an eon in samsāra with a visual simile.