Their life cycle works similar to this: Eggs are laid inside of your dog's intestine and pass out of your Golden Retriever through his bowel movements.
Once outside of your dog, it takes about 4 weeks for the embryos to mature, but they do not hatch then, as they wait until they are re-ingested into your dog before hatching.
If these cells are ingested by dogs before they have reached their first larvae cycle, they are simply re-passed again and will not actually be able to hatch inside of him.
After mature embryos are consumed by your pet, over the course of the next 2 to 3 months, the hatched egg will go through 4 more larvae growth stages in which they then become adults and are ready to breed and the cycle starts over again.
The eggs can survive in soil for many years.
Your Golden Retriever can get whipworms from walking on them, and then later licking his paws, or from chewing on items that have the eggs on them, such as grass and dirt.