5 ideas
Friendship should be acquired through testing, not granted on first warmth, because many friends are friends only while it suits them and turn away, or even become enemies, when trouble comes. The diagnostic is behavior under your misfortune: someone who shares your table in prosperity but vanishes in your distress was never a friend. A friend who proves faithful is a sturdy shelter worth more than any price.
The book commands lending to a neighbor in need and praises the good person who stands surety, yet it warns that when repayment comes due, some borrowers delay, make excuses and repay with resentment, so the lender may lose both money and friend. Surety has ruined some prosperous people, so it counsels helping according to one's means and taking care not to fall into ruin.
The same words can be wise or foolish depending on when they are spoken, so the skill lies in timing and restraint. The wise person listens first, answers only when they understand, and stays silent when they have nothing to say. The fool's thoughts sit on his tongue, and a slip of the tongue can do more damage than a fall on stone.
Farmers, smiths, engravers and potters sustain the fabric of the world, and no city could be inhabited without them. However, their minds are absorbed by the plow, the furnace and the wheel, so they are not called on for public counsel or judgment. The scribe's wisdom depends on having leisure to study law, prophecy and proverbs and to travel. Wisdom here is presented as a product of freed time, not only of native ability.
The book's long praise of the ancestors ends with Simon son of Onias, a high priest remembered for repairing and fortifying the Temple, digging a reservoir and strengthening Jerusalem against siege. It describes him coming out from the sanctuary 'like the morning star among the clouds' while the people bowed to receive his blessing. By closing the line of Israel's heroes with a recent high priest, the author links sacred history to the Temple order of his own era.