All Christians are sealed with the Holy Spirit or how long? Unto the day they lose their salvation? NO. Unto the day of redemption (Ephesians 4:30). Ephesians 1:13 - In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise, 14 who is the guarantee of our inheritance until the redemption of the purchased possession, to the praise of His glory.
There are genuine believers and there are make believers.
Jesus will say to many that He NEVER knew them because they were NEVER saved (Matthew 7:22-23).
The wording of the five foolish virgins in our text is all too familiar to the reader of Matthew’s Gospel:
Matthew 25:11 - "Later, the other virgins came too, saying, ‘Lord, lord! Let us in!’ 12 But he replied, ‘I tell you the truth, I do not know you!"
Matthew 7:21 - "Not everyone who says to me, ‘Lord, Lord,’ will enter into the kingdom of heaven" but only the one who does the will of my Father in heaven - (See John 6:40). 22 On that day, many will say to me, ‘Lord, Lord, didn’t we prophesy in your name, and in your name cast out demons and do many powerful works?’ 23 Then I will declare to them, 'I never knew you. Depart from Me, you who practice lawlessness!!’ (Matthew 7:21-23)
Taking Matthew’s words literally, I read that the difference between the foolish virgins and the wise virgins: The wise virgins had oil for their lamps, while the foolish virgins did not. The wise virgins had the opportunity to obtain oil, and did so. The foolish virgins had plenty of opportunity to procure oil, but did not.
It is possible to be in close contact with Christ, and with Christians, and yet not be saved. I am reminded of a similar passage in the Gospel of Luke:
Luke 13:23 Someone asked him, "Lord, will only a few be saved?" So he said to them, 24 "Exert every effort to enter through the narrow door, because many, I tell you, will try to enter and will not be able to. 25 Once the head of the house gets up and shuts the door, then you will stand outside and start to knock on the door and beg him, ‘Lord, let us in!’ But he will answer you, ‘I don’t know where you come from.’ 26 Then you will begin to say, ‘We ate and drank in your presence, and you taught in our streets.’ 27 But he will reply, ‘I don’t know where you come from! Go away from me, all you evildoers!’ 28 There will be weeping and gnashing of teeth when you see Abraham, Isaac, Jacob, and all the prophets in the kingdom of God but you yourselves thrown out. 29 Then people will come from east and west, and from north and south, and take their places at the banquet table in the kingdom of God. 30 But indeed, some are last who will be first, and some are first who will be last."
Jesus is warning us in this parable that there will be a number of people who look like Christians, who associate with Christians, and who even think they are Christians, who will be shocked to learn that they are not saved at the return of our Lord. What a sobering thought!