But Frigg wasn't done, oh no! The Aesir had tempted Fate's--practically danced on Fate's chest--and lost the gamble; rightfully Baldur needed to pay the cost like everyone. But Frigg wasn't done. She appealed to Hel, the goddess of the underworld (and #Loki's daughter, by the by), to release her son. Hel reasonably demanded proof of Frigg that Baldur really was SO wonderful and glowy that he deserved exemption from the rules that govern even the gods:

"If all things in the world, alive or dead, weep for him, then he will be allowed to return...If anyone speaks against him or refuses to cry, then he will remain with Hel."