Bel, or bael leaves, the leaves of the wood apple tree.

Aegle marmelos, commonly known as bael, Bengal quince,[1] golden apple,[1] stone apple, wood apple, bili,[2] is a species of tree native to India. It is present throughout Southeast Asia as a naturalized species.[3] The tree is considered to be sacred by Hindus. Its fruits are used in traditional medicine and as a food throughout its range.

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The word bilva (bel tree) is usually used as bilva-patra (leaf of bel). It is a sacred tree having sacrificial importance. Leaves of this sacred tree are generally trifoliate. This trifoliate leaf is symbolic of Trikal (brahma, vishnu and mahesh), Three eyes of lord shiva, Trishakti (Volition, action and knowledge), three lingas and three syllables of Omkar.

The bilva tree itself is so holy and auspicious that its worship or its significance is mentioned in many puranas and other scriptures at various instances. Here below is a narration of "greatness of bilva" under 22nd chapter in vidyesvarasamhita of shivapurana.

"The bilva is the symbol of lord shiva. It is adored even by the gods. It is difficult to understand its greatness. It can only be known to a certain extent. Whatever holy centre there is in the world finds a place under the root of bilva. He who worships mahadeva in the form of linga at the root of bilva becomes a purified soul. He shall certainly attain shiva. He, who pours water over his head at the root of a bilva, can be considered to have taken his bath in all sacred waters in the earth. Verily, he is holy. Seeing the water basin round the foot of the bilva tree full of water, shiva becomes greatly pleased. The man who worships the root of a bilva tree offering scents and flowers attains the region of shiva his happiness increases, his family flourishes. He who places a row of lighted lamps at the root of bilva tree with reverence becomes endowed with the knowledge of truth and merges into shiva. He who worships the bilva tree abounding in fresh tender sprouts becomes free from sins. If a man piously feeds a devotee of shiva at the root of a bilva tree he reaps the fruit thereof, ten million times more than in the usual course. He who makes a gift of rice cooked in milk and ghee to a devotee of shiva at the root of a bilva tree will never become poor."

Mahant Rama Shankar of Banaras wrote quoting the Skanda Purana and explained the origin of Bilva tree, "One day while Parvati was resting some drops of sweat fell from her forehead on the mountain Mandara, from which grew the bel tree, Girija lives on the root of the tree, Maheswari on its shoulder, Dukshayani on its branches, Parvati among its leaves, Katyayani in its fruit, Gaori in its flowers while in thorns the numerous Saktis find a home. It is also believed that Lakshmi, the Goddess of Wealth, also lives in the bel tree."

Those who perform the puja of Shiva and Parvati devoutly, using the leaves, will be endowed with spiritual powers.

Lakshmyaascha stana utpannam Mahaadeva sadaa priyam,
Bilva vriksham prayachchhaami eka bilvam Shivaarpanam.
Darshanam bilva vrikshasya sparshanam paapanaashanam,
Aghorapaapasamhaaram eka bilvam shivarpanam.

Born from the breasts of Goddess Lakshmi, the Bilva tree is ever dear to Mahadeva. So I ask this tree to offer a Bilva leaf to Lord Shiva. To have darshan of the Bilva tree, and to touch it, frees one from sin. The most terrible karma is destroyed when a Bilva leaf is offered to Lord Shiva.Sri Bilva Shtakam (v. 6–7)

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