Sunan al-Tirmidhi #2305
Sahih (Authentic)
Asceticism
لَوْ كَانَتِ الدُّنْيَا تَعْدِلُ عِنْدَ اللَّهِ جَنَاحَ بَعُوضَةٍ مَا سَقَى كَافِرًا مِنْهَا شَرْبَةَ مَاءٍ
The Messenger of Allah (ﷺ) said: 'If this world were worth the wing of a mosquito to Allah, He would not have given a disbeliever even a sip of water from it.'
Chaîne de narration (Isnad)
Narrated Sahl bin Sa'd