Chapter 3 first gives us some familiar instructions about honouring parents. Clearly this is aimed at grown up children honouring their elderly parents and, although not stated explicitly, it derives from the fact that this command when first given in the 10 commandments was accompanied by a promise, that those who obeyed it would live long in the land.
Then there is the injunction to be humble. Don’t concern yourself with matters that are beyond you. Have quiet faith, sit back and trust that God will do what is right. This is hard to swallow in today’s culture, when we all believe we have the right to know everything, and to be told that something is “none of your business” is an insult. Would it have been the same then? Plenty of people in the Bible questioned God - the Psalmist asked repeatedly why his prayers were not answered, or why underserved suffering came his way. If he’d listened to Sirach, we’d have had a shorter Psalter.