Do you know what your Lord has said?" They replied: "Allah and His Messenger know best." He said: "He has said: 'Some of My servants have entered the morning as believers in Me and some as disbelievers

Authentic

عَنْ زَيْدِ بْنِ خَالِدٍ الجُهَنِيِّ رضي الله عنه أَنَّهُ قَالَ: صَلَّى لَنَا رَسُولُ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ صَلَاةَ الصُّبْحِ بِالْحُدَيْبِيَةِ عَلَى إِثْرِ سَمَاءٍ كَانَتْ مِنَ اللَّيْلَةِ، فَلَمَّا انْصَرَفَ أَقْبَلَ عَلَى النَّاسِ، فَقَالَ: «هَلْ تَدْرُونَ مَاذَا قَالَ رَبُّكُمْ؟» قَالُوا: اللهُ وَرَسُولُهُ أَعْلَمُ، قَالَ: «أَصْبَحَ مِنْ عِبَادِي مُؤْمِنٌ بِي وَكَافِرٌ، فَأَمَّا مَنْ قَالَ: مُطِرْنَا بِفَضْلِ اللهِ وَرَحْمَتِهِ، فَذَلِكَ مُؤْمِنٌ بِي وَكَافِرٌ بِالْكَوْكَبِ، وَأَمَّا مَنْ قَالَ: بِنَوْءِ كَذَا وَكَذَا، فَذَلِكَ كَافِرٌ بِي وَمُؤْمِنٌ بِالْكَوْكَبِ».

Zayd ibn Khālid al-Juhani (may Allah be pleased with him) reported: The Messenger of Allah (may Allah’s peace and blessings be upon him) led us in the Fajr prayer at Al-Hudaybiyah after rainfall during the night. At the conclusion of the prayer, he turned toward the people and said: "Do you know what your Lord has said?" They replied: "Allah and His Messenger know best." He said: "He has said: 'Some of My servants have entered the morning as believers in Me and some as disbelievers. He who says, 'We have had rainfall by the grace and mercy of Allah' believes in Me and disbelieves in the stars, and he who says, 'We have had rainfall by the rising of such and such star' disbelieves in Me and believes in the stars.'"

Explanation

The Prophet (may Allah's peace and blessings be upon him) offered the Fajr prayer in Al-Hudaybiyah, a village close to Makkah, after rainfall at night. After he made taslīm and finished the prayer, he turned towards the people and asked them: Do you know what your Almighty Lord has said? They replied: Allah and His Messenger know best. He said: Allah Almighty clarified that people fall under two categories upon rainfall: believers in Allah Almighty and disbelievers in Him. Those who say, "We have had rainfall out of Allah's bounty and mercy," ascribing the rainfall to Allah, are believers in Allah, the Creator, and the Disposer of the affairs of the universe, and they disbelieve in the stars. And those who say, "We have had rainfall due to such and such star," are disbelievers in Allah and believers in the stars. But this is minor disbelief, as they attribute rainfall to a star, while Allah did not make it a cause of rainfall, neither in terms of the Shariah nor in terms of destiny. But as for those who ascribe rainfall and other earthly occurrences to the rise and decline of the stars, believing that they are the actual doer, they have fallen into major disbelief.

Benefits

It is recommended to say after rainfall: We have had rainfall out of the grace and mercy of Allah.
Those who attribute the blessing of rainfall and other things to the stars, believing that they create and bring them into existence, fall into major disbelief. But as for those who attribute rainfall to the stars in believing that they are a mere cause, they fall into minor disbelief, because the stars are not a Shar‘i or material cause for rainfall.
A blessing can be a cause of disbelief if it is denied or a cause of belief if recognized.
We are forbidden from saying "We have had rainfall due to such and such star," even if it refers to time, to block the means to polytheism.
Our hearts should be attached to Allah Almighty regarding bringing blessings and warding off afflictions.

Source · Agreed upon

From the Hadith Encyclopedia (hadeethenc.com).