The Buddha shares on how he knows of the release, liberation and independence for living beings.

At Sāvatthi.

Then, when the night had advanced, a certain deity having a beautiful appearance, illuminating almost the entire Jeta’s grove, approached the Blessed One. Having approached and greeted him, she stood to one side. Standing to one side, the deity said to the Blessed One: “Do you know, sir, the release, liberation, and independence for living beings?”

“I know, friend, the release, liberation, and independence for living beings,” replied the Blessed One.

“In what way then, sir, do you know the release, liberation, and independence for living beings?” asked the deity.

"With the exhaustion of delight in existence,

with the exhaustion of perception and consciousness;

with the ending of feelings and with tranquility,

Thus indeed, friend, I know;

the release, liberation, and independence for living beings."

Related Teachings:

Crossing the Flood (SN 1.1) - The Buddha crossed the flood of suffering without any support and without struggling.

There is That Base (Ud 8.1) - A way to understand Nibbāna is as a frame of reference that emerges from having let go of the frames of references (relating to the aggregate of perception and consciousness) of this world, the other world, of the jhānas, and/or of the formless attainments.

Navigating through 30 mental qualities that lead to enlightenment, to the arising of the Buddha (AN 10.76) - The Buddha lays down 30 different mental qualities in ten sets of threes that lead all the way to enlightenment. He explains them both backwards and forwards.