"he will certainly find divine service easy, for then he will not be lacking the proper attitude or preparation for it" a person who trains himself to have this conduct, where he's always ready to do what is right and necessary-he's not looking to be lazy- meaning he changes his outlook in his mind instead of looking for laziness and rest and indulgence and pleasures- he looks to do what is necessary. that's how he accustoms himself, "our sages have said "this is the way of torah -" eat bread with salt, drink water by measure and sleep upon the ground."