What is the sonnet "How Soon Hath Time" by John Milton about?

John Milton's sonnet "How Soon Hath Time" is a contemplation on the relationship between youth, adulthood and time. The sonnet is believed to have been written as a response to a friend who was pushing Milton to join the ministry and to stop studying and wasting his life.

The poem was written after Milton turned 24, suggested by the lines "How soon hath Time, the subtle thief of youth/Stol'n on his wing my three-and-twentieth year!" The sonnet explains that time is inevitable and that to worry about its passing is ill advised since only the "Task-Master," or God, is capable of controlling it.