"And among mankind is he who worships Allah as it were, upon the very edge (i.e., in doubt)..." (V.22:11) Sahih al-Bukhari 4742
Arabic hadith text
حَدَّثَنِي إِبْرَاهِيمُ بْنُ الْحَارِثِ، حَدَّثَنَا يَحْيَى بْنُ أَبِي بُكَيْرٍ، حَدَّثَنَا إِسْرَائِيلُ، عَنْ أَبِي حَصِينٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ {وَمِنَ النَّاسِ مَنْ يَعْبُدُ اللَّهَ عَلَى حَرْفٍ} قَالَ كَانَ الرَّجُلُ يَقْدَمُ الْمَدِينَةَ، فَإِنْ وَلَدَتِ امْرَأَتُهُ غُلاَمًا، وَنُتِجَتْ خَيْلُهُ قَالَهَذَا دِينٌ صَالِحٌ. وَإِنْ لَمْ تَلِدِ امْرَأَتُهُ وَلَمْ تُنْتَجْ خَيْلُهُ قَالَ هَذَا دِينُ سُوءٍ.
Translation
Narrated Ibn `Abbas
Regarding the Verse: "And among men is he who worships Allah's as it were on the very edge." (22.11). A man used to come to Medina as if his wife brought a son and his mares produces offspring. He would say, "This religion (Islam) is good," but if his wife did not give birth to a child and his mares produced no offspring, he would say, "This religion is bad."