The third essential element of a valid contract is the presence of ‘consideration’. Consideration has been defined as the price paid by one party for the promise of the other. An agreement is legally enforceable only when each of the parties to it gives something and gets something. The something given or obtained is the price for the promise and is called ‘consideration’ subject to certain exceptions; gratuitous promises are not enforceable at law.
The ‘consideration’ may be an act (doing something) or forbearance (not doing something) or a promise to do or not to do something. It may be past, present or future. But only those considerations are valid which are ‘lawful’. The consideration is ‘lawful’. unless it is forbidden by law; or is of such a nature that, if permitted it would defeat The provisions of any law; or is fraudulent; or involves or implies injury to the person or property of another; or is immoral; or is opposed to public policy (sec.23).