Muwatta Malik 959

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ مَثَلُ الْمُجَاهِدِ فِي سَبِيلِ اللَّهِ كَمَثَلِ الصَّائِمِ الْقَائِمِ الدَّائِمِ الَّذِي لا يَفْتُرُ مِنْ صَلاَةٍ وَلاَ صِيَامٍ حَتَّى يَرْجِعَ ‏"‏ ‏.‏

Yahya related to me from Malik from Abu'z-Zinad from al-Araj from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, said "Someone who does jihad in the way of Allah is like someone who fasts and prays constantly and who does not slacken from his prayer and fasting until he returns

Reference

Muwatta Malik 959

In-book

Book 21, Hadith 1