Jesus told his disciples this parable: “The Kingdom of heaven will be like ten virgins who took their lamps and went out to meet the bridegroom. Five of them were foolish and five were wise. The foolish ones, when taking their lamps, brought no oil with them, but the wise brought flasks of oil with their lamps. Since the bridegroom was long delayed, they all became drowsy and fell asleep. At midnight, there was a cry, ‘Behold, the bridegroom! Come out to meet him!' Then all those virgins got up and trimmed their lamps. The foolish ones said to the wise, ‘Give us some of your oil, for our lamps are going out.' But the wise ones replied, ‘No, for there may not be enough for us and you. Go instead to the merchants and buy some for yourselves.' While they went off to buy it, the bridegroom came and those who were ready went into the wedding feast with him. Then the door was locked. Afterwards the other virgins came and said, ‘Lord, Lord, open the door for us!' But he said in reply, ‘Amen, I say to you, I do not know you.' Therefore, stay awake, for you know neither the day nor the hour.”
In the gospel according to Matthew, Jesus used three parables to warn us one thing: be prepared for the second coming of the Lord.
In the parable of the ten virgins, the bridegroom is Jesus Christ, the ten virgins waiting for bridegroom is the church, and entering into the wedding feast is entering into the kingdom of heaven. In the Lord's prayer we often pray, "Thy kingdom come," but no one knows when will Jesus come again and take us into His kingdom. And because we don't know, while there's still some time to wait, Jesus warns us that some people would take things easy and fail to live out God's teachings. And He'll say to them, "I do not know you." Just like the five foolish virgins who brought the lamps but not having enough oil, even if they try to seek help from others, it'll be too late and the door will be locked in front of them.
Therefore, be always prepared for the bridegroom's arrival, then no matter when He arrives, we'll be ready for Him and be able to enter His kingdom with Him.
“Be vigilant at all times and pray that you have the strength to escape the tribulations that are imminent and to stand before the Son of Man.” (Luke 21:36)