Spielvogel, 2009). Hobbes cites two ways to attain absolute monarchy; by institution and by acquisition. The first one is achieved by voluntary agreement among a multitude of people wherein the selection of the sovereign power is done through the casting of votes or similar. He states that the main reason why people want a commonwealth by institution is because of fear of one another; they want a greater power to dictate the direction where everyone should go to avoid the possibility of everyone going against everyone else due to their opposing points-of-view. On the other hand, the second one requires the use of force by the sovereign power wherein people subject themselves under him due to fear of death or any other punishment should they choose otherwise.

When a sovereign power is put into place whether by institution or by acquisition, Hobbes...

The benefit of the unity that comes with this structure is two-fold. For one, they are able to live at peace with each other because submitting all wills into the will of one sovereign power eliminates the possibility of warring with one another. Secondly, they are protected against other men for a group of united people is without a doubt much stronger than a mere individual and has more capability of subduing entities that might oppose them.
References

Hobbes, Thomas. Oxford World's Classics -- Thomas Hobbes Leviathan. Oxford: Oxford University Press, 1998.

Spielvogel, Jackson. Western Civilization (7th ed.). California: Thomson Learning, Inc., 2009.