Mishkat al-Masabih 1 Faith كتاب الإيمان 39

عَن وهب بن مُنَبّه قِيلَ لَهُ: أَلَيْسَ لَا إِلَهَ إِلَّا اللَّهُ مِفْتَاحُ الْجَنَّةِ قَالَ بَلَى وَلَكِنْ لَيْسَ مِفْتَاحٌ إِلَّا لَهُ أَسْنَانٌ فَإِنْ جِئْتَ بِمِفْتَاحٍ لَهُ أَسْنَانٌ فَتَحَ لَكَ وَإِلَّا لَمْ يَفْتَحْ لَكَ. رَوَاهُ الْبُخَارِيُّ فِي تَرْجَمَة بَاب

Wahb b. Munabbih, on being asked whether ‘There is no god but God’ was not the key of paradise, said, “Yes, but every key has wards. If you bring a key with wards the door will be opened for you, otherwise I it will not.” Bukhari transmitted it in a chapter heading.