From Sahih Muslim (Hadith 6504):
Abdullah b. 'Amr reported that a person came to Allah's Apostle (ﷺ) and sought permission (to participate) in Jihad, whereupon he (the Holy Prophet) said:Are your parents living? He said: Yes. Thereupon he (the Holy Prophet) said: You should put in your best efforts (in their) service
Reference: Muslim 6504