Indra once happened to see Surabahi, the Kamadhenu (divine cow), crying in the Indraloka. Indra asked he why she was crying.
Surabhi then described the troubles that her children are going through in the world. She told him that her sons were ploughing without rest. They were always tied to the yoke of farmers.
She said that she was overwhelmed by their sufferings and tears rolled out from her eyes.
Indra’s heart melted due to the tears of Surabhi.
Indra then caused heavy showers in the world, when ploughing became impossible. Thus the sons of Surabhi (oxen) got rest in the world.