The bond happens as you fiind people that take care of their clients as you would.
Hope that helps.
The Real Estate Settlement Procedures Act (a.k.a., RESPA) has specific prohibitions about money changing hands between parties to a transaction, like between a realtor and a loan company, for residential transactions. The intent is to keep kickbacks from occuring that would "tie" a realtor to a lender. So, technically speaking, there should be no direct financial incentive for a realtor to be "bonded" to a specific lender.
That said, Charles is correct, we as realtors, would like to have a degree of trust in the relationships that we have when helping buyers and sellers in a real estate transaction. Having a number of lenders that we can recommend, who will compete for your business, is just prudent business practice.
But as Charles also pointed out, not only are you free to use any lender, because you probably don't know that much about your agent other than what you've learned in the short time you've had them representing you, you should also (must!) get competitive quotes from lenders we have not recommended. It really is the only way to know that the ones your realtor has recommended, are competitive.
If you find 1 lender on your own that seems to beat the pants off everyone else's offer, look at that particular lender with a bit of skepticism. If you're doing a good job at comparing offerings, there won't be whopping difference between any of them, if there is, something's probably not right. In the end, if one of the lenders that your agent recommended is competitive, strongly consider going with that lender as the trust that your realtor has established will probably go a long way to a smooth transaction.
We can work with all lenders, but just like you would want to work with someone you know and trust, I do the same thing. Building a good relationship with a lender(s) is one thing thing that all Realtors must do. You want to have a couple of lenders that you know will meet the needs of your clients. You have lenders that specialize in residential or commercial and one may have a program that another doesn't, so you search for the one that will best suit your clients needs. You of course have the right to use any lender that you like.
I hope that this helps.