2. In contracts there must always be a consideration in order to make them valid. This is sometimes mutual, as when one man promises to pay a sum of money to another in consideration that he shall deliver him a horse, and the latter promises to deliver him the horse in consideration of being paid the price agreed upon. When a man and a woman promise to marry each other, the promise is mutual. It is one of the qualities of an award, that it be mutual; but this doctrine is not as strict now as formerly. 3 Rand. 94; see 3 Caines 254; 4 Day, 422; 1 Dall. 364, 365; 6 Greenl. 247; 8 Greenl. 315; 6 Pick. 148.
3. To entitle a contracting party to a specific performance of an agreement, it must be mutual, for otherwise it will not be compelled. 1 Sch. & Lef. 18; Bunb. 111; Newl. Contr. 152. See Rose. Civ. Ev. 261.
4. A distinction has been made between mutual debts and mutual credits. The former term is more limited in its signification than the latter. In bankrupt cases where a person was indebted to the bankrupt in a sum payable at a future day, and the bankrupt owed him a smaller sum which was then due; this, though in strictness, not a mutual debt, was holden to be a mutual credit. 1 Atk. 228, 230; 7 T. R. 378; Burge on Sur. 455, 457.