"The world is an illusion"

When someone tells the world is an illusion, kindly ask how it can be so. what is the value of such a teaching in the said illusory world.

Decent teachings put many good persons on a nice path to walk. They also warn against associating with fools. [Apannaka Sutta]

The Bhagavad Gita 16:7 and onwards tells

demoniac . . . say that this world is unreal [and] rise as the enemies of the world . . . deluded. (Excerpts from Srila Prabhupada's Bhagavad Gita As It Is, 16. 6-16)

The Bhagavad Gita on demons and their works (chap. 16) may put illusion teachings in perspective.

Yogananda excerpts

The demonic know not the right path of action . . . They lack purity and truth and proper conduct. (7) They say: "The world has no moral foundation, no abiding truth . . . (8)

They are enemies of the world, bent on its destruction. (9)

. . . they strive . . . by amassing wealth dishonestly. (12)

(Yogananda (and SRF). The Yoga of the Bhagavad Gita (2007, 16:7-16, excerpts)

Meditation

Buddha says:

Those things that I have known with direct knowledge but have not taught are far more numerous [than what I have taught]. And why haven't I taught them? Because they do not lead to to calm, to direct knowledge, to self-awakening.

"And what have I taught? The path of practice leading to the cessation of dukka (suffering, stress, etc). [More]

The hub of Buddha's benign all-round way "on and up" in life is meditation. Moral and sound ways and dealings go into it too. [More]

Among researched meditation methods, the all-round most helpful is Transcendental Meditation. [◦Research findings]