Musar su Salmi 16:3

In light of the above I believe we can now understand the statement in Perek Shirah (Chapter 5) that the song recited daily by the ox is the refrain, “I will sing to Hashem because He has exalted Himself over the exalted, etc.” (Shemos 15:1). In other words, the essence of the ox’s acknowledgement and praise of Hashem is that pride and grandeur are fitting only to Him, but not to human beings, as it states, “Hashem has begun His reign, He has clothed Himself with majesty” (Tehillim 93:1). Since the entire month of Nissan is a time of favor, the holy souls make no delay in praying on our behalf. Thus it states, “Due to the holy ones who are in the earth and the mighty, all my desires are [fulfilled] through them” (Tehillim 16:3). They demonstrate their concern for the woes of human beings at all times. For instance, whenever an evil decree is issued, Heaven forbid, they are quick to pray for its rescission. In general, however, they are not permitted to reveal the matter explicitly to human beings. Only on occasion do they come to someone in a dream and reveal it through hints and the like. Thus we find (Shalsheles HaKabbalah, p. 139) that Rabbeinu Yechiel, father of Rabbeinu Asher, had a pious companion whom he loved very much. Both men were elders of the community and both were renowned for their great deeds and their exceptional learning and piety. They swore to one another that whichever of them died first would come to the survivor in a dream and inform him of the ways of death and the subsequent journeys of the soul.