This was said by the Blessed One, said by the Arahant, as I have heard:
“Bhikkhus, I do not see any other single barrier, obstructed by which, beings have wandered on and undergone |repeated existence::wandering on from one state of existence to another, the cycle of birth and death, moving on continuously [saṁsāra]| for a long time, like this barrier of |ignorance::fundamental unawareness or misunderstanding of the true nature of reality, not experientially understanding the four noble truths [avijjā]|. Indeed, bhikkhus, it is because beings are obstructed by the barrier of ignorance that they have wandered on and undergone repeated existence for a long time.”
The Blessed One spoke on this matter. In this regard, it is said:
“There is no other single thing,
surrounded by which, beings,
wander on day and night,
as when surrounded by |illusion::delusion, hallucination, misapprehension, distorted view; that which fuels further confusion and doubt [moha]|.
But those who have put an end to illusion,
and have shattered the mountain of ignorance;
They do not undergo repeated existence,
for the cause no longer exists for them.”
This matter too was spoken by the Blessed One, as I have heard.