Sahih al-Bukhari 6423
Narrated `Utban bin Malik Al-Ansari:
who was one of the men of the tribe of Bani Salim: Allah's Messenger (ﷺ) came to me and said, "If anybody 
comes on the Day of Resurrection who has said: La ilaha illal-lah, sincerely, with the intention to win 
Allah's Pleasure, Allah will make the Hell-Fire forbidden for him."
قَالَ سَمِعْتُ عِتْبَانَ بْنَ مَالِكٍ الأَنْصَارِيَّ، ثُمَّ أَحَدَ بَنِي سَالِمٍ قَالَ غَدَا عَلَىَّ رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏
"‏ لَنْ يُوَافِيَ عَبْدٌ يَوْمَ الْقِيَامَةِ يَقُولُ لاَ إِلَهَ إِلاَّ اللَّهُ‏.‏ يَبْتَغِي بِهِ وَجْهَ اللَّهِ، إِلاَّ حَرَّمَ اللَّهُ عَلَيْهِ النَّارَ ‏"‏‏.‏