Every person alive and who has ever lived has grown up in a certain town or country or church or time that has shaped how they understand and interpret everything around them. That's culture, and we all have it. It colors everything.
For example, tell a boy from America to brush his teeth, and he will go to a tiled room, turn on a faucet, and rub a plastic thing in his mouth. Tell a boy from Bangladesh, and he will step outside, get a bucket of water and a branch.
When approaching the Bible, some people would say that we should take absolutely no thought of culture--the culture in which it was written or the culture in which we now live--because to do so would be namby-pamby. That we should simply read the Scripture bereft of any trifling concerns about culture.
If we could all do this, I agree, it would be excellent. Sola Scriptura.
However, this presents one huge problem. To assume we approach Scripture empty-handed and empty-minded is foolish, and in my opinion, phenomenally arrogant. Sometimes we Americans can think we are neutral. We don't see the way we do things or view things as weird or different, but just the way things are. Because we subtly perceive ourselves as the neutral and normal ones, we then think we can approach Scripture as blank slates.
It's simply an untruth. Every person has their own culture which has shaped how they understand words and concepts. Say "family" to us, and we're going to think of one dad, one mom, and three children living in a little brick house somewhere. We will interpret any verse we read about family based on what we think "family" means.
Say "family" to a person living in some parts of Africa, and they will think of a much larger group of people. Grandmothers, aunts, cousins, all living in one compound. That person will then read and understand any verse about the family in this context. He therefore might have a very different understanding about it than I would.
Neither of us would have intended to interpret Scripture based on our own culture, but our own failure to acknowledge that we have culture and that it affects how we view everything would in fact be what allowed our culture to sway how we understand the Bible.
We are foolish when we assume we are the ones who approach Sola Scriptura without hauling behind us a huge suitcase full of culture.