Shiva and Parvati were very happy at the services rendered by their son Ganesha. For the destruction of the demon Taraka Asura, a second son was born to them. His name was Skanda. Because He had six faces, He was known as "Shanmukha." And as He was born when the "kritloka" stars were auspicious, He was also known as "Kartekeya." The whole universe adored Him with the name "Subrahmanya," as He blessed His devotees with the knowledge of Brahman.
The universal parents, Shiva and Parvati, thought of marriage for their two sons, Ganesha and Subrahmanya, as they had attained youth-the right time for marriage. When their parents revealed the decision for them to marry, the two boys began quarreling.,
One said, "marry me first!"
"No," the other rejoined, "marry me first!"
To pacify them, Shiva and Parvati devised a plan, called them near, and spoke to them thus, "O good sons, we love both of you equally. To settle your quarrel, we have made a decision. Between the two of you, whoever returns here first after going around the entire Mother Earth shall be married first !"
On hearing these words, Lord Subrahmanya immediately set off on His peacock with great speed to go around the earth quickly and return earlier than Ganesha. To their wonderment, Lord Ganesha just stood near Lord Shiva and Shakti Parvati without making any preparations to leave. Instead, He requested that His divine parents occupy the two seats He provided and prayed to them to accept His worship service. Shiva and Shakti readily agreed to this and sat on those seats.
Lord Ganesha worshipped both of them with great devotion, circumambulated seven times and made obeisance to them seven times. As He completed His seventh salutation, Lord Subrahmanya arrived, completing His journey around the entire earth. Now Subrahmanya demanded that His marriage be celebrated first because He had gone around the earth and returned to them first, as per their command. Lord Ganesha never went around the earth at all.
At this point, Lord Ganesha said, "O Divine Mother, O Universal Father, the Vedas declare that whoever goes around or circumnavigates his parents obtains the fruit of bhu-pradakshina or tones circling around the entire earth. When this blessing is applicable even by going around earthly parents, how much more it should be when the circumnavigation is done to you, O Divine Parents. By going around you seven times, I have gone around not only the earth, but the whole universe! Therefore, celebrate my marriage without any delay."
On hearing Ganesha's intelligent words, Shiva and Parvati were pleased and at once decided to celebrate His marriage first. Prajapati Vishwaroopa's two beautiful daughters, one called Riddhi and the other called Siddhi, were selected to marry Lord Ganesha. The divine sculptor Vishwakarma made all the arrangements for the marriage by constructing a beautiful marriage hall. Lord Shiva and Parvati celebrated the marriage of Ganesha to Riddhi and Siddhi, who bore Him two beautiful sons named Labha and Kshema respectively.
Ganesha is an eternal brahmachari (celibate). All the gods are, but they "marry" sometimes so that we people on mundane earth will understand. Thus, Ganesha married two beautiful daughters of Brahma the Creator, and they are called "Riddhi" and "Siddhi." The illumined mind and attainment. The energies or powers of God are His wives. And out of these two wives, Ganesha had two children. One is called Kshema. Another is called Labha. Labha means profit, gain of the highest wealth. And Kshema means complete protection of that highest wealth.
Lord Subrahmanya, who silently observed all this, bade farewell to His parents and brother and went to the Krauncha Mountain near Lake Manasa in Kailasa Mountain. (In Skanda Puraana, the story of Subrahmanya is narrated, where it is explained that after the marriage of Ganesha, Subrahmanya also was married to two beautiful wives named Valli and Devasena.)