On Hinduism

Hindus who choose to go to temples or have a temple at home, offering food is an approach to strengthen devotion. For others it is the aspect of giving something of importance, which strengthens their material detachment. To others it is the solace of donating food that can be used for feeding the temple priests or even the poor and the hungry. Hinduism permits different vehicles of piety, practices and devotion. Offering food, with many different motivations behind it, is yet another example of the many vehicles of devotion that Hindus choose.

Hindus can offer water, leaves, fruits or flowers as an expression of their devotion. That which comes from the divine is being offered back as prasad–this is an important way to remember the source of all material opulence.

It is important to recognize that not all Hindus go to temples nor all Hindus believe in going to temples. In fact, there are schools of thought within Hinduism that do not have temples or don’t believing in offering to any deity.

Other reading material: What is prasad?

Relevant videos: 

Contributor: Rajeev Singh

Location of this post (18c): https://www.hinduspeakers.org/ufaqs/why-do-you-give-food-to-god-idols/

Lamps were the only source of artificial light in olden days. Consider a dark room, where God, a symbol/representation of the divine, is placed (in the sanctum of temples). The priest shows a lamp in the form of Aarathi close to the murti. The purpose is to make sure the picture is registered in our minds.
Light represents knowledge. When praying we are saying that the Lord gives me enough knowledge all the time.

Other reading material:
Relevant videos:

Contributor: Dr. Jyoti Lulla

Location of this post (18d): https://www.hinduspeakers.org/ufaqs/why-do-you-use-light-aarti-to-pray/