his saying the star rose in the darkness means that the pleiades rose in the sky in the remaining darkness of the night. and harvest the grass it is time to harvest its dryness.
قوله استقل النجم فى غلس ، يريد ارتفعت الثريا فى السماء ببقية من غلس الليل. و احصد البقل ، حان أن يحصد لجفوفه.