Sunan An-Nasa'i

It was narrated that Shurahbil bin As-Simt said to Ka'b bin Murrah:""O Ka'b! Tell us a Hadith from the Messenger of Allah (ﷺ) and be careful."" He said: ""I heard him say: 'Whoever develops one gray hair in Islam, in the cause of Allah, it will be light for him on the Day of Resurrection.'"" He said to him: ""Tell us about the Prophet (ﷺ) and be careful."" He said: ""I heard him say: 'Shoot, and whoever hits the enemy with an arrow, Allah will raise him one degree in status thereby.'"" Ibn An-Nahhan said: 'O Messenger of Allah, what is a degree?' He said: 'It is not like the doorstep of your mother; [1] rather (the distance) between two degrees is (that if) a hundred years.'"" [1] As explained after it; the degree of distance is greater than such a degree in this world