There can be a stranger to a consideration but not a stranger to a contract, signifies that a consideration may move from

Under Section 2(d) of the Indian Contract Act, 1872, consideration must move at the desire of the promisor. The consideration can come from the promisee or any other person (a 'stranger' to the consideration), but every person who is not a party to the contract is a 'stranger' to the contract itself. This principle distinguishes between who provides consideration and who can enforce the contract.