Ignorance. Translated by Bhikkhu Bodhi

Sitting to one side, that bhikkhu said to the Blessed One: “Venerable sir, it is said, ‘ignorance, ignorance.’ What is ignorance, venerable sir, and in what way is one immersed in ignorance?”

“Bhikkhu, not knowing suffering, not knowing the origin of suffering, not knowing the cessation of suffering, not knowing the way leading to the cessation of suffering: this is called ignorance, bhikkhu, and it is in this way that one is immersed in ignorance.

“Therefore, bhikkhu, an exertion should be made to understand: ‘This is suffering.’ An exertion should be made to understand: ‘This is the origin of suffering.’ An exertion should be made to understand: ‘This is the cessation of suffering.’ An exertion should be made to understand: ‘This is the way leading to the cessation of suffering.’”

The Buddha's words/Avijjāsutta SN 56.17