'A’isha told that when God’s messenger was asked by some people about kahins he replied, “They are of no account.” They said, “Messenger of God, they sometimes tell a thing which is true.” He replied, “That is a word pertaining to truth which a jinni snatches and cackles into the ear of his friend as a hen does; then they mix more than a hundred lies with it.” (Bukhari and Muslim.)
Source: sunnah.com
Other translations
Arabic
وَعَن عَائِشَة قَالَتْ: سَأَلَ أُنَاسٌ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَنِ الْكُهَّانِ فَقَالَ لَهُمْ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِنَّهُمْ لَيْسُوا بِشَيْءٍ» قَالُوا: يَا رَسُولَ اللَّهِ فَإِنَّهُمْ يُحَدِّثُونَ أَحْيَانًا بِالشَّيْءِ يَكُونُ حَقًّا فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «تِلْكَ الْكَلِمَةُ مِنَ الْحَقِّ يَخْطَفُهَا الْجِنِّيُّ فَيَقُرُّهَا فِي أُذُنِ وَلَيِّهِ قَرَّ الدَّجَاجَةِ فَيَخْلِطُونَ فِيهَا أَكْثَرَ مِنْ مِائَةِ كذبة»
sunnah.com