Ulum al Qur'an
'Free' and 'Bound' Verses
Some of the ahkam verses are valid, 'free' (mutlaq) from any conditions or circumstances, while others are 'bound' (muqayyad) to special conditions or situations, and apply only therein.
Examples:
'If it is beyond your means, fast for three days, that is expiation for the wrath ye have sworn' (Al-Qur'an 5: 92).
It is free, i.e. left to one's discretion whether to fast three days consecutively or with interruptions.
'And if ye find no water then take yourselves clean sand or earth and rub therewith your faces and hands' (Al-Qur'an 5: 6). [Some say this aya is 'bound', as the same aya mentioning wudu' instructs washing of the hands 'to the elbows'; others say it is 'free'.]