Before I went on my recent diet I must confess that I was a somewhat regular visitor to a local donut shop. While visiting there I saw part of this proverb fulfilled on a regular basis. I would watch well dressed businessmen come in and buy two dozen donuts of various types and then head out for their important appointment. Now I do not think these businessmen were donut freaks - they were just using the donuts to gain access to a customer. Every man is a friend to him who gives gifts - especially when those gifts are donuts early in the morning.
Some proverbs are meant to help us understand human nature. This is one of them. The fact is that many men will seek the favor of a generous man. The word for "generous" here means more than just someone who is giving. It also means a noble man - one born of nobility - which also usually means a wealthy man - and one connected in such a way that he has power. The simple fact of life is that many will seek this man's favor because of what he offers to them. This is why people in high positions should be careful about those who are courting their favor. It is a very rare thing for people in these kind of positions to find people who want nothing from them but friendship.
The man who gives gifts will have many friends. But - there is a flip side to this as well. If you have the majority of your friends because of how generous you are - be careful to seek to court true friends in the midst of them. When the gifts cease often so does their friendship. That is why you want no only to be generous toward others - but also discerning. Generous because it is a good thing to learn to be generous toward others - but discerning as well because you also want to know who are real friends are in life. In the end - they will be the ones who will stick with you no matter what your bottom line is - or what your gifts will help to make theirs.