The mutual transferring of right, is that which men call “contract.”

There is difference between transferring of right to the thing; and transferring, or tradition, that is delivery of the thing itself. For the thing may be delivered together with the translation of the right; as in buying and selling with ready money; or exchange of goods, or lands; and it may be delivered some time after.

Again, one of the contractors may deliver the thing contracted for on his part, and leave the other to perform his part at some determinate time after, and in the meantime be trusted; and then the contract on his part is called “pact,” or “covenant”: or both parts may contract now, to perform hereafter; in which cases, he that is to perform in time to come, being trusted, his performance is called “keeping of promise,” or faith; and the failing of performance, if it be voluntary, “violation of faith.”