Wahb ibn Munabbih was asked, “Isn’t the key to Paradise the kalimah La ilaha illallah (the testification that ‘none has the right to be worshiped save Allah’)?”

أليس مفتاح الجنة لا إله إلا الله؟

He replied, “Of course, but every key has its teeth: if you bring a key that has the right teeth, the door shall open; but if not, it will not.”

بَلى، ولكنْ ليسَ مِفتاحٌ إلاّ لهُ أسنانٌ فإن جئتَ بمفتاحٍ له أسنانٌ فُتِحَ لك، وإلاّ لم يُفَتحْ لك

[Bukhari, Kitab al-Jana’iz]

(Read on pgs 32, Ibn Rajab al-Hanbali, The Key to Paradise. Daar us-Sunnah Publishers. Birmingham: 2007.)