Abdullah bin Busr reported,
Two Arab nomads came to the Prophet ﷺ. One of them asked, "Muhammad, who are the best of men?"The Prophet ﷺ replied, "Those whose lives are long and whose deeds are good."The other said, "The laws of Islam have become many for us. Give us a comprehensive matter we can hold fast to."He answered, "Let your tongue remain moist with the remembrance of Allah 
."
Ahmad 17680
Sahihحدثنا علي بن عياش حدثنا حسان بن نوح عن عمرو بن قيس
عن عبد الله بن بسر قال
أتى النبي ﷺ أعرابيان فقال أحدهما من خير الرجال يا محمد قال النبي ﷺ من طال عمره وحسن عمله وقال الآخر إن شرائع الإسلام قد كثرت علينا فباب نتمسك به جامع قال لا يزال لسانك رطبا من ذكر الله عز وجل
Its isnad is sahih. Ali bin Ayyash is Alhani Hims, the imam, and he is trustworthy and firm in memory. Bukhari and the four (Sunan compilers) narrated from him. Hassan bin Nuh Nasri, Abu Umaya Hims, is among the trustworthy successors. Amr bin Qays bin Thawr bin Mazin, Abu Thawr Hims, is among the trustworthy successors.The first part of the hadith was narrated by Tirmidhi, 4/565, number 2329, in the chapter on asceticism, on what has been said about long life, on the authority of Abdullah bin Busr, and he said, hasan sahih. Haythami rated its chain sound, 10/203.As for the second part, it was also narrated by Tirmidhi, 5/458, number 3375, in the chapter on supplication, on what has been said about the merit of remembrance, and he said, hasan gharib. Ibn Majah narrated it similarly, 2/1246, number 3793, in the chapter on manners. Ibn Abu Shayba narrated it similarly to Tirmidhi, 10/301, number 9502. Hakim graded it sahih, 1/495, and Dhahabi endorsed it.