It was narrated from Ibn 'Abbas that the Prophet P.B.U.H said: "Whoever makes a vow and does not state it specifically, the expiation (for such a vow) is the expiation for breaking an oath, Whoever makes a vow and is not able to fuIfill it, the expiation for that is the expiation for breaking an oa tho Whoever makes a vow and is able to fulfill it, let him do so," (Hasan)