From Sahih Bukhari (Hadith 2797):
Narrated Abu Huraira:The Prophet (ﷺ) said, "By Him in Whose Hands my life is! Were it not for some men amongst the believers who dislike to be left behind me and whom I cannot provide with means of conveyance, I would certainly never remain behind any Sariya' (army-unit) setting out in Allah's Cause. By Him in Whose Hands my life is! I would love to be martyred in Allah's Cause and then get resurrected and then get martyred, and then get resurrected again and then get martyred and then get resurrected again and then get martyred
Reference: Bukhari 2797