Among Allah's Signs, He sends down the Rain and brings forth the Produce
Allah tells;
وَهُوَ الَّذِي يُرْسِلُ الرِّيَاحَ بُشْرًا
And it is He Who sends the winds as heralds of glad tidings,
After Allah stated that He created the heavens and earth and that He is the Owner and Possessor of the affairs Who makes things subservient (for mankind), He ordained that He be invoked in Du`a, for He is able to do all things. Allah also stated that He is the Sustainer and He resurrects the dead on the Day of Resurrection.
Here, Allah said that He sends the wind that spreads the clouds that are laden with rain.
Allah said in another Ayah,
وَمِنْ ءَايَـتِهِ أَن يُرْسِلَ الرِّيَـحَ مُبَشِّرَتٍ
And among His signs is this, that He sends the winds with glad tidings. (30;46)
Allah's statement,
بَيْنَ يَدَيْ رَحْمَتِهِ
going before His mercy,
means, before the rain.
Allah also said;
وَهُوَ الَّذِى يُنَزِّلُ الْغَيْثَ مِن بَعْدِ مَا قَنَطُواْ وَيَنشُرُ رَحْمَتَهُ وَهُوَ الْوَلِىُّ الْحَمِيدُ
And He it is Who sends down the rain after they have despaired, and spreads His mercy. And He is Al-Wali (the Guardian), Al-Hamid (the praiseworthy). (42;28)
and,
فَانظُرْ إِلَى ءَاثَـرِ رَحْمَةِ اللَّهِ كَيْفَ يُحْىِ الاٌّرْضَ بَعْدَ مَوْتِهَأ إِنَّ ذَلِكَ لَمُحْىِ الْمَوْتَى وَهُوَ عَلَى كُلِّ شَىْءٍ قَدِيرٌ
Look then at the results of Allah's mercy, how He revives the earth after its death. Verily, that (is the one Who) shall indeed raise the dead, and He is able to do all things. (30;50)
Allah said next,
حَتَّى إِذَا أَقَلَّتْ سَحَابًا ثِقَالاً
Till when they have carried a heavy-laden cloud,
when the wind carries clouds that are heavy with rain, and this is why these clouds are heavy, close to the earth, and their color is dark.
Allah's statement,
سُقْنَاهُ لِبَلَدٍ مَّيِّتٍ
We drive it to a land that is dead,
that is, a dry land that does not have any vegetation.
This Ayah is similar to another Ayah,
وَءَايَةٌ لَّهُمُ الاٌّرْضُ الْمَيْتَةُ أَحْيَيْنَـهَا
And a sign for them is the dead land. We give it life. (36;33)
This is why Allah said here,
فَأَنزَلْنَا بِهِ الْمَاء فَأَخْرَجْنَا بِهِ مِن كُلِّ الثَّمَرَاتِ كَذَلِكَ نُخْرِجُ الْموْتَى
Then We produce every kind of fruit therewith. Similarly, We shall raise up the dead.
meaning, just as We bring life to dead land, We shall raise up the dead on the Day of Resurrection, after they have disintegrated.
Allah will send down rain from the sky and the rain will pour on the earth for forty days. The corpses will then be brought up in their graves, just as the seeds become grow in the ground (on receiving rain).
Allah often mentions this similarity in the Qur'an when He gives the example of what will happen on the Day of Resurrection, and bringing life to dead land,
لَعَلَّكُمْ تَذَكَّرُونَ
so that you may remember or take heed.
Allah's statement