The reason making them light is part of the Sunnah is the report that the time God takes to reckon with all His servants together on the Day of Resurrection is like the two cycles of the dawn Sunnah. He therefore made them light out of mercy for his community. In sum, it is prayer and comes under the ruling of prayer.
Although prayers apart from the obligations are servanthood of choice, there is a likeness of servanthood of necessity in the two cycles of the dawn Sunnah because voluntary prayer contains obligatory acts.
The servant in voluntary prayer and in prayers apart from the obligations is like a slave of whom a share has been freed, or one under a contract of manumission, or one promised freedom at his master’s death.[58] These bear traces of freedom absent from the slave who has none of these conditions. The state of servanthood in those voluntary acts that are Sunnahs is that of the slave under a contract of manumission or promised freedom at his master’s death.
A voluntary prayer that is not a Sunnah, meaning that he, may God bless him and grant him peace, neither performed it regularly nor specified it in his words, is like a slave of whom a share has been freed. He is free in respect of what has been freed and a slave in respect of what remains unfreed. This is a state of servanthood between servanthood of necessity and servanthood of choice, just as the Sunnahs stand between the obligations and the voluntary acts.
Those who hold that only the Opening should be recited in these cycles do so because it suffices. Through it his act is valid as prayer.
As for those who add a surah after the Opening,
Notes
[58]
(The author borrows the degrees of manumission to explain differing rulings of worship. The freedom of the mukātab depends on fulfilling the manumission contract, while that of the mudabbar is appointed for after his master’s death. The comparison here concerns the conjunction of an aspect of obligation and an aspect of choice.)
