يُرۡسِلِ ٱلسَّمَآءَ عَلَيۡكُم مِّدۡرَارًا
He will send [rain from] the sky upon you in [continuing] showers
The word مِّدۡرَارًا describes rain that comes continuously, abundantly, life-giving rain—the kind that’s controlled and beneficial, not destructive.
This is particularly powerful in retrospect, because the punishment that ultimately destroyed this nation was also water—but water gone wild, uncontrolled, catastrophic.
The same element that could have been a blessing became an instrument of destruction.
Rain, when it comes as Allah intends, is a source of vegetation, healthy society, flourishing life.
That blessing was offered to them through istighfar.
When Umar (may Allah be pleased with him) went out to pray for rain during a drought and did nothing more than seek forgiveness, the people around him asked, “Didn’t you pray for rain?” He replied, “I knocked on the doors of the sky through which rain comes down,” and then recited this ayah. In the gathering of Hasan al-Basri, a man complained of drought. He told him, “Seek forgiveness.” When another complained of financial hardship, another of having no children, and another of his land being barren, he told each of them the same thing. When those around him found this strange, he recited this ayah.