And when he knew by this that He, glorified and exalted is He, is severe in seizing, and that the effort of the one who strives does not avail him, he caused his saying to warn them against following Pharaoh: "So how will you protect yourselves?" meaning, how will you find the protection that will shield yourselves? And since the deterrence from the cause of the threat is more significant, for it indicates the mercy of the one warning and motivates avoidance of it, he said, indicating with a tool of doubt that their disbelief in Allah, along with what He has established for them of rational proofs supported by transmitted evidence, should not exist in any way. Rather, it is mentioned as a hypothesis and estimation: "If you disbelieve," meaning, you have placed a veil over what has been planted in your natures of the lights of the proofs leading to faith, so you remain in your disbelief - while the expression indicates that He has pardoned them for the past disbelief, so it is not counted against them as a mercy from Him and generosity, nor is it counted against them except for what they have committed after the coming of the Messenger, blessings and peace be upon him. "A day" [meaning] it is a metaphor for severity, whereby it is said in it: "He will make" for the severity of its horrors and its earthquakes and its terrors. "Children" meaning at birth or near it. "Gray hair" is the plural of ashyab, which is from the whiteness of his hair, and that is a metaphor for the abundance of worries in it, for it is customary that when they intensify, they hasten the graying. The meaning is the denial that they can make for themselves a protection with all their effort that will shield them from the punishment of that day described with this greatest horror, and that is when Allah says: "O Adam, arise and send forth the batch for the fire from every thousand, nine hundred and ninety-nine." And he attributed the making to the day because it occurs in it, just as the one who is pious is made, and indeed the pious is the punishment that occurs in it.