What does Genji mean when he says that the Buddha is trying to teach him that the world
slips away?

Genji Shimada shouts "Ryujin no ken wo kurae!" when he uses his ultimate, which roughly translates to "Take my Dragonblade!". Hanzo Shimada shouts "Ryuu ga waga teki wo kurau!" when he uses his ultimate, which roughly translates to "Let the dragon consume my enemies!".      

Explanation:

answer; (a) he was a u.s senator for 38 years;