This is a section out of a class I taught a few months back, I thought it might be helpful to you:
11:1 Cast your bread upon the waters,
for you will find it after many days.
2 Give a portion to seven, or even to eight,
for you know not what disaster may happen on earth.
There is a substantial amount of question over exactly what point is of these verses. I mean, is he talking about crumbling up your French bread and dumping it in the river?
[As a side note, there is a reason I like to bring up when there is discussion over these issues; that is my opinion on the difference in the function of preaching and teaching. If I were to preach these texts I would primarily be concerned with proclaiming them, and thus would most likely (unless it was something very thorny or difficult to decide upon) take what I thought to be the best understanding of the text and preach it. Proclaim it. Exhort obedience to “thus says the Lord.” I think that is the job of the preacher, to proclaim the word of God. I think the task of a teacher in a setting like this is somewhat different, in that I want to help you come to your own understanding of the text. Not that a preacher is unconcerned with that, but there is a difference between coming to the best possible understanding of the text and proclaiming that, as opposed to laying out multiple legitimate understandings and arguing for what you feel is probably the best and most helpful one.]
What are the options on the table for understanding these verses? Well in verse one, Solomon says to cast your bread upon the waters. There is a possibility that he is making an agricultural reference here. Apparently the ancient Egyptians (whose culture and practices Solomon would have been quite familiar with) had a custom of taking their “bread corn” out on the Nile river when it was at flood stage, throwing it out into the water, and then as the waters receded, the corn would be covered in silt and sprout and grow in the formerly flooded area. So they’d be throwing out their bread, as it were, and finding it after many days. That’s possible. I don't think it's real likely, but it's possible. And a very vivid mental picture.
The second possibility, the one taken by most modern commentators, is that Solomon is talking about financial diversity. He was involved in international commerce via ship, and so by sending one’s bread out on the waters he means the shipping of grain over the seas. Invest in this way, and it will come back. But be sure to take into account verse two, and send it out to seven or eight (not necessarily those precise numbers, just get spread out) so that you don’t have all your eggs in the proverbial single basket. The idea would be much akin to investing in mutual funds, rather than placing all your stock in Apple. Or Gateway. That would have gone badly for you.
The third option, held by most of the older commentators, and the one that I think is probably right, is that Solomon is speaking metaphorically here; that he doesn’t have actual water in mind. Rather, he is saying, be generous with what you have been given, give to the poor, and do so in all directions. It will come back to you in the form of blessing (perhaps financial, perhaps only spiritual). And do so to seven, even eight, that is, be liberal with whom you bless, don’t make people jump through hoops to receive your generosity, just be generous: you never know where it’s going to pay off in their life or yours. You don’t know what friends you might make for yourself. And come the day of disaster, those very friends may be the ones who are there for you.
I think this final option makes the most sense because this is Wisdom literature, and a dominate form of communication is that of metaphor. In fact, it wouldn't be a stretch to say that Solomon is talking about generosity, but that there is the concrete reference point in his mind of the ships going out to sea, of bread heading over the waters, to come back again.
So what are we to learn? Be generous. We are often tempted to think that we best provide for ourselves and our future by hoarding; Solomon says give it away. Give liberally in the knowledge that good will come of it, either now or in the future.