The witnesses must not refuse when they are called , and do not consider it wearisome to write it down , whether it be a big or small sum , [ as a loan lent ] until its term . That is more just with Allah and more upright in respect to testimony , and the likeliest way to avoid doubt , unless it is an on-the-spot deal you transact between yourselves , in which case there is no sin upon you not to write it .