Spend your time in your important matters and distractions, and do not empty yourself except at night. You should engage in conversing with Allah, which requires a clear mind and the absence of distractions. As for reading with the letter 'khā', it is a metaphor from the fluffing of wool: it is its fluffing and spreading of its parts, for the spreading of worry and the scattering of the heart due to distractions. He was tasked with standing in prayer at night, then he mentioned the wisdom behind this task: that the night is more helpful for concentration and better for reading, due to the calmness of a man and the lowering of his voice. It is also more encompassing for the heart and more effective in alleviating worries than the day, because it is the time of the dispersal of worries and the distribution of thoughts, and the turning over of needs for this life and the Hereafter. It was said that it provides space and freedom for your sleep and your management of your needs. It was also said: if you miss something from the night, you have free time in the day in which you can catch up on it.