Why is this the answer?

The answer is beehive because this clever riddle uses special word pictures to describe the amazing home of a bee colony. Let us break down the riddle into three secret clues and see how they fit perfectly together. The very first clue says, "Thousands lay up gold within this house." If you think about what a bee makes, the "gold" is the sweet, sticky honey they store for food. The "thousands" are all the very busy worker bees who fly from flower to flower collecting nectar and turning it into their food. And the "house" where they put all their golden treasure is the beehive itself, which is a wonderful place full of little wax compartments called honeycomb. Then the riddle tells us, "But no man made it." This is important because the bees are super smart builders. While people sometimes help by giving them a wooden box, the bees build all the tiny, six-sided honeycomb cells inside the hive themselves. It is a natural home made by insects, not by a person's hands. The bees know exactly how to engineer their house to keep their family and their food safe and secure. The final part of the riddle gives us the best clue about protection: "Spears past counting guard this house, but no man wards it." This is a little scary, but it describes the one thing that protects the hive: the bees' stingers. The stingers are like tiny "spears." The riddle says there are "spears past counting" because there are so many bees in the colony, ready to defend their home and their honey. The phrase "no man wards it" means there is no human guard, like a soldier or a security person. The thousands of bees are the ones who stand watch over their house all by themselves. That is why a beehive is the perfect answer to this imaginative riddle.