Al Hasan said to al Farazdaq while he was burying his wife, what had he prepared for this day.
He said “bearing witness that laa ilaaha illAllah (there is no god worthy of worship except Allah), for seventy years.” Al Hasan said “What a good preparation, but laa ilaaha illAllah has conditions, so beware of accusing a chaste woman.” And it was said to al Hasan “Indeed there are people saying ‘Whoever says laa ilaaha illAllah will enter Paradise'”, so he said “Whoever says laa ilaaha illAllah and fulfills its right and obligation will enter Paradise.”And Wahb bin Munabbih said to the one who asked him “Isn’t laa ilaaha illAllah the key to Paradise?” He said “Definitely, but there is no key except that it has teeth, so if you come with a key having teeth, it will open for you, and if not, it will not open for you.”
[From the book Kalimat al Ikhlās wa Tahqīq Ma’nāhā 📚 by that Ibn Rajab]