Explain the Meaning of Kierkegaard's Claim: "If There Were No

Explain the meaning of Kierkegaard's claim: "if there were no sacred bond which united mankind, if one generation arose after another like the leafage in the forest, if the one generation replaced the other like the song of birds in the forest, if the human race passed through the world as the ship goes through the sea, like the wind through the desert, a thoughtless and fruitless activity, if an eternal oblivion were always lurking hungrily for its prey and there was no power strong enough to wrest it from its maw" then life would be empty.