During the Second World War, we were told ‘careless talk costs lives’ and that theme seems to have come from Proverbs 13: “Careful words make for a careful life; careless talk may ruin everything.” (Prov 13:2) 
This chapter has plenty more to say about how we talk: “A good person hates false talk; a bad person wallows in gibberish.” (Prov 13:5), and “The good acquire a taste for helpful conversation; bullies push and shove their way through life” (Prov 13:2), for example. It also talks a lot about how to live: with common sense (vs 16), with a listening ear (vs 1), with diligence (vs 4, 11) and with loyalty to God (vs 13, 21).
There are some very famous verses in here, notably Proverbs 13:12 (‘hope deferred makes the heart sick, but a longing fulfilled is a tree of life’) and Proverbs 13:24 (‘Whoever spares the rod hates their children, but the one who loves their children is careful to discipline them.’) These verses can obviously be taken out of context, but I’m sure we’ve all experienced that sense of unrelenting disappointment which saps energy and enthusiasm from life and we all know that a lack of discipline ultimately leads to disaster. The Bible reminds us constantly that we reap what we sow and we need to careful to do what is right in God’s eyes, not being squeezed into the world’s mould or thinking that it has all the answers to life when it so clearly doesn’t.