In Paul's letter to the church at Thessalonica, he warned them against idleness. What he referred to was the idleness of not earning your way in the world. Not doing the work of the Lord with the purpose He had in mind for your life.
He points to himself as the example of working while teaching. This was not because his teaching was not worthy of payment, but because he wanted to show them the industriousness that needs to accompany the teacher. It is not enough to sit idly by and just think in an ivory tower. One needs to have the experience of the work at hand to base one's theories upon.
I don't believe it is any accident that this warning immediately follows Paul's dissertation on the second coming of Christ. Early church fathers knew and accepted the principle that our time is short (in light of eternity) and that we must be busy about the Lord's work.
The book of Proverbs was well known in Paul's time. I memorized Proverbs 29:18 in the KJV when I was a child.
Sometimes it is a struggle to see the vision God has for your life. When the world seems to cave in upon you, when everything you thought you had is ripped away, when tragedy and destruction mark your path, you have great difficulty seeing a vision of your purpose in God's world.Those minutes and hours, once spent, are irredeemable.
Our purpose is to serve the Lord and His church. For that we need all the time eternity can offer.
Teach us to number our days so that we may give a good account of them when Your Son returns. Grant that we may be useful in Your kingdom. Help us to see the vision You have for our lives.
In Jesus' most precious name.