Bali Mahārāja wanted to give charity to Vāmanadeva, but the Lord expanded His body in such a way that He showed Bali Mahārāja that everything in the universe is already in His body. Actually, no one can give anything to the Supreme Personality of Godhead, for He is full in everything. Sometimes we see a devotee offering Ganges water to the Ganges. After taking his bath in the Ganges, a devotee takes a palmful of water and offers it back to the Ganges. Actually, when one takes a palmful of water from the Ganges, the Ganges does not lose anything, and similarly if a devotee offers a palmful of water to the Ganges, the Ganges does not increase in any way. But by such an offering, the devotee becomes celebrated as a devotee of mother Ganges. Similarly, when we offer anything with devotion and faith, what we offer does not belong to us, nor does it enrich the opulence of the Supreme Personality of Godhead. But if one offers whatever he has in his possession, he becomes a recognized devotee. In this regard, the example is given that when one's face is decorated with a garland and sandalwood pulp, the reflection of one's face in a mirror automatically becomes beautiful. The original source of everything is the Supreme Personality of Godhead, who is our original source also. Therefore when the Supreme Personality of Godhead is decorated, the devotees and all living entities are decorated automatically.
(Srimad Bhagavatam------8:20:21----------purport).

Lord Śiva's touch saved the demon from committing suicide; his bodily injuries immediately healed, and his body became as it was before. Then Lord Śiva told the demon, "My dear Vṛkāsura, you do not need to cut off your head. You may ask from me any benediction you like, and I shall fulfill your desire. I do not know why you wanted to cut off your head to satisfy me. I become satisfied even by an offering of a little water." Actually, according to the Vedic process, the śiva-liṅga in the temple or the form of Lord Śiva in the temple is worshiped simply by offering Ganges water, because it is said that Lord Śiva is greatly satisfied when Ganges water is poured upon his head. Generally, devotees offer Ganges water and the leaves of the bilva tree, which are especially meant for offering to Lord Śiva and Goddess Durgā. The fruit of this tree is also offered to Lord Śiva. Lord Śiva assured Vṛkāsura that he is satisfied by a very simple process of worship. Why then was he so eager to cut off his head, and why was he taking so much pain by cutting his body to pieces and offering it in the fire? There was no need of such severe penances. Anyway, out of compassion and sympathy, Lord Śiva prepared to give him any benediction he liked.
(Krsna Book).