Passage
Boast not thyself of tomorrow; For thou knowest not what a day may bring forth.
Boast not thyself of tomorrow; For thou knowest not what a day may bring forth.
Proverbs 27:1 Boast not thyself of tomorrow; For thou knowest not what a day may bring forth.
Proverbs 27:2 Let another man praise thee, and not thine own mouth; A stranger, and not thine own lips.
Proverbs 27:3 A stone is heavy, and the sand weighty; But a fool`s vexation is heavier than they both.
The verse centers on "boast", "thyself", "tomorrow", "thou", "knowest", "bring", and "forth". It is saying that the verse draws attention to "boast" and "thyself", so its meaning should be read from those terms before moving to application.
The next verse adds "Let another man praise thee and not...", so "boast" and "thyself" should be read forward into that movement. In Proverbs context, the local focus is covenant, worship, and faithfulness.
A plain takeaway is to answer the verse's own emphasis on "boast" and "thyself" with trust shaped by these words, not by a vague optimism outside the passage.