There are debates all over that try to talk about GOD - where there exists a single GOD, or is there a plurality...
I don't take any stance here, but thought this interesting thought on GOD is worth a note...
Most of us would have heard the acronym for GOD - Generator, Observer, Destroyer, and in the Hindu Mythology, we call these roles performed as being performed by Tridev - Brahma, Vishnu, Shiva. Brahma takes the role of the Creator; Vishnu that of the Manager of happening of life, and Shiva the Destroyer who closes life as such!
These gods are generally accompanied by their consorts - Saraswthy, Lakshmi and Parvathy respectively. Saraswathi is considered the Goddess of Knowledge, Lakshmi the Goddess of Wealth, and Parvathy the Goddess of Power.
Combining the Gods with their consorts, we have Brahma who is married to Sarawathy, Lakshmi who is the wife of Vishnu and Parvathy who is with Shiva. If we are to abstract this a bit - would could take the action performed and the corresponding representations we have- Brahma the creator is with Saraswathy who represents knowledge - the underlying implication being that - "to create something new, you got to possess the knowledge. Similarly,for one to sustain and manage an existing set up, finance place a primarily role and that seems to be logic highlighted in Vishnu-Lakshmi as a pair.Also, to get to close aspects or issue that have grown beyond the point of control, use of power become mandatory - possibly represented by the pairing of Shiva and Parvathy.
Why have these three Gods: Why not have them all in one?
It is but usual for one to ask, cant all these be handled by a single GOD? Why have three or them and what advantage would it actually get to the table?
Very often we find that people who create things fall in love with their creation, they would like tobe so closely associated with their creation that they would no more realize the direction in which the creation is proceeding...it is best done with by someone else who get in an expertise on taking care of things and has the decision of taking the creation in the right direction. In the process of creation, its is always possible that the manager could be so enticed into maintaining that he/she could possibly not realize that the creation has outlived the utility.
Where one's responsibility ends the other begins. This however is not to state that they don't discuss or realize that at places there is a need to collaborate.
In fact, Shiva who generally comes in the phase of destruction is also considered an expert on knowledge and learning - from what gets closed or destroyed, it is important to realize that learning are crucial and an means to improve the next cycle...So in some form, even Shiva is seen as an epitome of knowledge accrued over ages and generations.
Why do the pictures generally show them meditating?
The tasks these GODs do is very sensitive, if not delicate; and it is important to create a balance between action and involvement at the mental and physical level. Less said the better - these are extremely high pressure roles!.
Meditation enable self-reflection, which allows these high pressure jobs be analyzed in a perspective that disassociate the problem from the individual and focus on solving the problem and lesser of blaming it on the individual.