Daniel, in the first-person singular, turned to Yahweh, and not the God of heaven or the Most High God, as earlier in this book. This was the traditional Hebrew name of Yahweh. Daniel assumed the traditional role of a penitent with prayers and supplications while fasting, and wearing sackcloth with ashes on him.
Sirach reminds us that we should respect other people. We should not make fun of ill bred people because some of our ancestors might be insulted. We should not criticize a penitent, since all of us deserve punishment. We should not make fun of old people because some of us are getting old. We should not rejoice over the death of anyone because we too are going to die.