Mishkat al-Masabih 1510
Abu Huraira said:
I heard God’s Messenger say that a prophet took the people out to pray for rain, and when he saw an ant raising some of its legs to the sky he said, “Return, for your prayers have been answered because of this ant.”

Daraqutni transmitted it.
وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: 
" خَرَجَ نَبِيٌّ مِنَ الْأَنْبِيَاءِ بِالنَّاسِ يَسْتَسْقِي فَإِذا هُوَ بنملة رَافِعَة بعض قوائهما إِلَى السَّمَاءِ فَقَالَ: ارْجِعُوا فَقَدِ اسْتُجِيبَ لَكُمْ من أجل هَذِه النملة ". رَوَاهُ الدَّارَقُطْنِيّ