Tanya Chapter 39 part 1

Animals are instinctive beings of our physical world. But there are instinctive beings in the higher worlds too – these are the angels. Their powerful instincts of love or fear of Hashem are sublime and magnificent. However, it is a nature which they did not create by choice, by which they simply operate. From this we can appreciate the power of our own service, even if we cannot produce any new emotions, serving Hashem by tapping into the instincts of our soul. Our service then is at least as powerful as that of these mighty instinctive beings, the angels. Since the angels operate by instinct, their abode is in the world of Yetzirah. But the abode of the righteous who serve Hashem with intellectual love and fear, created out of free choice, is beyond that of the angels in the world of Beriah.