Rumi (1207-1273) captive bird, a story from Masnavi.

Rumi, Sadi and others used stories to convey morals. Masnavi has many and here is one.

A certain man caught a bird by guile and trap; the bird said to him, “O noble sire,thou hast eaten many oxen and sheep, thou hast sacrificed many camels;Thou hast never in the world been sated(satisfied) by them, neither wilt thou be sated by my limbs. Let me go, that I may bestow on thee three counsels, that thou mayest perceive whether I am wise or foolish. (I will give thee) the first of those counsels on thy hand, the second of them on thy plastered roof, and the third counsel I will give thee on a tree. (let me go), for thou will become fortunate through these three counsels.  (As for) that saying which is (to be said) on thy hand, ‘tis this; ‘do not believe an absurdity (when thou hearest it) from anyone.’”When it (the bird) had uttered the first grave counsel on his palm, it became free and went (to perch) on the wall of his house,And said, “The second is, ‘do not grieve over (what is) past; when it has passed from thee, do not feel regret for it.”After that, it said to him, “In my body is concealed a solitary (large and precious) pearl 10 dirhems in weight.By thy soul’s truth (as sure as thou livest), that jewel was thy fortune and the luck of thy children.Thou hast missed the pearl, for it was not thy appointed lot (to gain it)—a pearl the like of which is not in existence.”——Khwaja began to cry out clamorously.The bird said to him, Did not I admonish thee, saying, ‘Let there be no grief in thee for what passed yesterday’?Since it is the past and gone , why art thou grieving? Either thou didst not understand my counsel or thou art deaf.And (as regards) the second counsel I gave thee, (namely), ‘Do not from misguidedness put any belief in an absurd statement,’O lion, I do not myself weigh 10 dirhems ; how should the weight of 10 dirhems be within me?”The khwaja came back to himself (recovered from his wits) and said, “Hark, disclose the third (piece of) excellent counsel.”“Yes,” said the bird, “thou hast made good use of those (former counsels), that I should tell (thee) the third counsel in vain!”To give counsel to a sleepy ignoramus is to scatter seed in nitrous soil.The rent of folly and ignorance does not admit of being patched up; do not give the seed of wisdom to him (the fool), O counselor.