The eleventh hour is the last possible moment at which something can be done before problems or solutions might arise. The phrase, “at the eleventh” hour became popular in the 19th century, but was in use much earlier. It alludes specifically to the book of Matthew in the New Testament (20:2-16).
This account in Matthew is a parable regarding workers who arrive at the eleventh hour of the workday and are still paid a full day’s wage. Biblical scholars have suggested that the parable can mean that even people who come to Christianity late in life will still earn the full benefits of the joys of eternal life.
Some scholars have even placed this hour as specifically the hour between 5 and 6 pm, since the typical workday would have been from sunup to sunset, or between 6am and 6 pm. This very literal meaning seldom applies to eleventh hour as it is used commonly. Instead, it simply means “at the last possible time.”
Some relate “at the eleventh hour” to procrastination, and view the phrase in a negative sense. For example, Constantine’s deathbed conversion to Christianity seems unfair to some Christians, as it happened at the very last moment. A student who waits until the night before it's due to write a paper or finish an assignment has certainly procrastinated, and may turn in work that is not carefully thought out or well-prepared.
In other circumstances, a last minute solution is viewed positively. For example in the sentence, “At the eleventh hour, the Teachers’ Union and the School Board were able to negotiate a contract,” the phrase is used positively. If the contract hadn’t been negotiated, then the Teachers’ Union might have had to go on strike. In other words, sometimes solution that arrives just in the nick of time saves the day.
At other times, a problem may present itself at the eleventh hour, which delays something being accomplished. A family who has been packing all day for a trip might have their trip delayed at the last moment by the baby suddenly running a fever. Such problems are generally unwelcome occurrences.