But if thou shalt forbear
chadal (khaw-dal')
to be flabby, i.e. (by implication) desist; (figuratively) be lacking or idle -- cease, end, fall, forbear, forsake, leave (off), let alone, rest, be unoccupied, want.
to vow
nadar (naw-dar')
to promise (pos., to do or give something to God) -- (make a) vow.
it shall be no sin
chet' (khate)
a crime or its penalty -- fault, grievously, offence, (punishment of) sin.
in thee