The Prophet ﷺ said, "The one who strives in the path of Allah is guaranteed by Allah, either to be taken into His forgiveness and mercy, or to be returned with reward and spoils. The likeness of the one who strives in the path of Allah is like that of a person fasting and standing in prayer, who does not slacken until he returns."
حدثنا أبو بكر بن أبي شيبة وأبو كريب قالا حدثنا عبيد الله بن موسى عن شيبان عن فراس عن عطية
عن النبي ﷺ قال المجاهد في سبيل الله مضمون على الله إما أن يكفته إلى مغفرته ورحمته وإما أن يرجعه بأجر وغنيمة ومثل المجاهد في سبيل الله كمثل الصائم القائم الذي لا يفتر حتى يرجع
[Hasan]: Ibn Abu Shayba, the author's teacher, narrated it in Musannaf (5/319) from Ubaydullah, from him. See hadith no. 37 regarding the status of Atiya. This hadith has corroborating narrations in Muslim, no. 1878, and Tirmidhi, no. 1620, among others.