Surah Sad (Sad), Verse 44

وَخُذْ بِیَدِكَ ضِغْثًا فَاضْرِبْ بِّهٖ وَلَا تَحْنَثْ اِنَّا وَجَدْنٰهُ صَابِرًا نِّعْمَ الْعَبْدُ اِنَّهٗۤ اَوَّابٌ ۟

Wa khuz biyadika dighsan fadrib bihee wa laa tahnas, innaa wajadnaahu saabiraa; ni'mal 'abd; innahooo awwaab

“"And take in thy hand a little grass, and strike therewith: and break not (thy oath)." Truly We found him full of patience and constancy. How excellent in Our service! ever did he turn (to Us)!”

Quran 38:44 (Yusuf Ali Translation)