The metaphor of investment

Matthew 25:24–27 (English Standard Version):
He also who had received the one talent came forward, saying, “Master, I knew you to be a hard man, reaping where you did not sow, and gathering where you scattered no seed, so I was afraid, and I went and hid your talent in the ground. Here, you have what is yours.” But his master answered him, “You wicked and slothful servant! You knew that I reap where I have not sown and gather where I scattered no seed? Then you ought to have invested my money with the bankers, and at my coming I should have received what was my own with interest.”
What is it to “invest with the bankers” so as to generate “interest”? This extension of the parable’s financial metaphor has always puzzled me.

I haven’t read any commentaries on this passage. I should. (I shall.)

What I record here is just a brainstorm, a feeble speculation.

The next parable – that of the Sheep and Goats – clears up the puzzle, as follows.

Verses 37–39:
Then the righteous will answer him, saying, “Lord, when did we see you hungry and feed you, or thirsty and give you drink? And when did we see you a stranger and welcome you, or naked and clothe you? And when did we see you sick or in prison and visit you?”
Put differently (in the language of the Parable of the Talents):

Master, while you were away we didn’t do anything for you. We didn’t add to your store. We may as well have buried our wealth – that is, your wealth, entrusted to us – in the ground.

The Master replies (verse 40):
Truly, I say to you, as you did it to one of the least of these my brothers, you did it to me.
Put differently:

See these guys? My brothers? The people in your church? They’re my wealth. You served them. You improved their value. And some of them, thanks to your help, enlisted more brothers for me or enriched me in other ways. By aiding them, you helped to enrich me further.

Most of the Sheep will accept this response, but some especially hapless one might feel compelled to press the issue:

Yes, Master, I served your brothers, all right, but none of them did much for you, either. Their efforts were sterile. (Or, in some cases, they died before they could devote themselves to your service.) My investment came to nothing.

It does happen.

The Master, however, could reply:

Whether the investment paid off or not wasn’t up to you, though, was it? When a steward deposits a little money into the bank, the bank doesn’t always augment it. That’s not the steward’s fault.

By putting money into the bank, you have done a sensible and responsible thing. …

My family – the church – the bank – is generally a fruitful place for investing; as such, it is an appropriate taker for a person with but little to give.

Those entrusted with more will be able to make some riskier investments for me. Some of those investments will pay off handsomely. Then I’ll reap out of proportion to what I have sowed.

But not all of my stewards are in a position to make this sort of investment.

What my stewards must do is to invest what they’ve been given. That might just amount to feeding, clothing, welcoming, or comforting other Christians, who don’t always pay it forward but nevertheless can best be expected to do so. Because I will be helping them. Because, ultimately, I run the bank.