The term Peter uses is made up of two words, with one referring literally to “intestines.” Bowels have a way of giving expression to emotional tension. In this case the sort of emotional tension Peter desires is “good” (the other word making up the term Peter uses) and so generates the notion of compassion, mercy, tender-heartedness (see further Luke 1:78). The reference to “intestines” makes clear that Peter is not encouraging a superficial or shallow level of emotion but something deep-seated, one that gets to the pit of one’s stomach. When feelings go that deep for each other, brotherly love of necessity engenders sympathy and in turn spawns unity of mind.