The Book of Miscellany
كتاب المقدمات
(74) Chapter: Clemency, Tolerance and Gentleness
(74) - باب الحلم والأناة والرفق
Riyad as-Salihin 636 
Anas (May Allah be pleased with him) reported:
The Prophet (ﷺ) said, "Make things easy and do not make them difficult, cheer the people up by conveying glad tidings to them and do not repulse (them)."

[Al-Bukhari and Muslim].

وعن أنس رضي الله عنه عن النبى صلى الله عليه وسلم قال‏:‏ “يسروا ولا تعسروا وبشروا ولا تنفروا ‏(‏‏(‏متفق عليه‏)‏‏)‏‏.‏
Reference : Riyad as-Salihin 636
In-book reference : Introduction, Hadith 636