If only a sign had been sent down to him. It is said that 'sent down' means 'caused to descend.' It has been recited as 'to descend' with both emphasis and without emphasis. The verb and the subject are feminine because the femininity of 'sign' is not real, and it is appropriate for separation. They said this despite the abundance of signs sent down to the Messenger of Allah, blessings and peace be upon him, due to their refusal to acknowledge what was sent down to him, as if nothing had been sent down to him out of their stubbornness. Say, 'Indeed, Allah is capable of sending down a sign that compels them to believe.' Like the turning of the mountain upon the Children of Israel and similar events, or a sign that if they deny it, punishment would come to them. But most of them do not know that Allah is capable of sending down that sign, and that there is a wise reason preventing Him from sending it.