Exodus 37:3
And he cast for it four rings of gold, to be set by the four corners of it; even two rings upon the one side of it, and two rings upon the other side of it. And he cast for it four rings of gold, to be set by the four corners of it; even two rings upon the one side of it, and two rings upon the other side of it.
The casting of four gold rings for the ark was one specific detail of the larger work God directed Moses to have carried out for the sanctuary. Those rings belonged to the tabernacle and its vessels, which were fashioned from solid gold with skillful workmanship intended to beautify the sanctuary. Skillful men performed the construction, while women contributed embroidery worked in silver and gold.
This exact, divinely specified sanctuary work stands in parallel with the directions God gave to Noah for building the immense ark that preserved him and his family.