The pronoun in 'مِرْيَةٍ مِنْهُ' refers to the Qur'an or the Messenger, blessings and peace be upon him. 'The barren day': the day of Badr. The day of war is described as barren because the children of women are killed in it, making them as if they are barren and have not given birth. Or because the fighters are referred to as the sons of war, and when they are killed, the day of war is described as barren in a figurative sense. It is said: it is a day that has no good in it. It is said: a barren wind if it does not bring rain or pollinate trees. It is also said: there is no comparison to it in the greatness of its matter for the fighting of the angels, peace be upon them, in it. And from Al-Dhahhak, it is the Day of Resurrection, and what is meant by 'the hour' is its precedents. It is permissible that what is meant by 'the hour' and 'a barren day' is the Day of Resurrection, as if it is said: until the hour comes to them or its punishment comes to them, so 'يَوْمٍ عَقِيمٍ' is placed in the position of the pronoun.