(Proverbs 27:1 KJV) Boast not thyself of to morrow; for thou knowest not what a day may bring forth.
Boasting should be passive not active. By that I mean that it should be done about you, not by you. The word means to praise and when we praise ourselves we are being a bit self centered. When it comes to “tomorrow” (4279) what kind of things do we usually boast about? I would think it is expectations we have for our own performance. So it is a preemptive patting ourselves on the back.
Boasting is contrasted to faith and trust. We are to walk quietly in faith, praising God and lifting Him up. We are not to be loud and assertive.
So? We face tomorrow with confidence. That does not mean we are to try to talk ourselves or others into believing that all will be well. It means that we are to act like all will be well. You have heard the saying about how the person who is calm doesn’t understand the situation? In this case we don’t need to understand the situation because we serve the one who controls the situation.