Al-Bukhari reported: It was said to Wahb ibn Munabbih, may Allah have mercy on him, “Is not the key to Paradise the statement: There is no god but Allah?” Whab said, “Of course, but rather every key has ridges. If you come with the correct key, the door will be opened for you; otherwise, it will never open.”
Source: Ṣaḥīḥ al-Bukhārī 2/71
Grade: Sahih (authentic) according to Al-Bukhari
عن البخاري قِيلَ لِوَهْبِ بْنِ مُنَبِّهٍ رحمه الله أَلَيْسَ لَا إِلَهَ إِلَّا اللَّهُ مِفْتَاحُ الْجَنَّةِ قَالَ بَلَى وَلَكِنْ لَيْسَ مِفْتَاحٌ إِلَّا لَهُ أَسْنَانٌ فَإِنْ جِئْتَ بِمِفْتَاحٍ لَهُ أَسْنَانٌ فُتِحَ لَكَ وَإِلَّا لَمْ يُفْتَحْ لَكَ
2/71 صحيح البخاري كتاب الجنائز باب ما جاء في الجنائز ومن كان آخر كلامه لا إله إلا الله