The Oil Represents Character

Every true follower of Christ has a work to do. God has given to every man his work. A few are now pointing to the roll of fast-fulfilling prophecy and proclaiming, Get ready, show your obedience to God by keeping His commandments. This is no time for the messengers of God to stop to prop up those who know the truth, and who have every advantage. Let them go on to lift the standard and give the warning, "Behold, the Bridegroom cometh; go ye out to meet Him." Many who hear the message--by far the greatest number--will not credit the solemn warning. Many will be found disloyal to the commandments of God, which are a test of character. The Lord's servants will be called enthusiasts. Ministers will warn the people not to listen to them. Noah received the same treatment while the Spirit of God was urging him to give the message, whether men would hear or whether they would forbear. 
     Come when it may, the advent of Christ will surprise the false teachers who are saying, "Peace and safety;" "all things continue as they were from the beginning." Thus saith the word of Inspiration, "Sudden destruction cometh upon them." The day of God shall come as a snare upon all who dwell upon the face of the whole earth. It comes to them as a prowling thief. "If the goodman of the house had known in what watch the thief would come, he would have watched, and would not have suffered his house to be broken up." Habitual watching is our only safety. We must be ever ready, that that day may not overtake us as a thief. 
     Let everyone who loves God consider that now while it is day is the time to work, not among the sheep already in the fold, but to go out in search of the lost and perishing ones. These need to have special help to bring them back to the fold. Now is the time for the careless to arouse from their slumber. Now is the time to entreat that souls shall not only hear the word of God, but without delay secure oil in their vessels with their lamps. That oil is the righteousness of Christ. It represents character, and character is not transferable. No man can secure it for another. Each must obtain for himself a character purified from every stain of sin.  

     The Lord is coming in power and great glory. It will then be His work to make a complete separation between the righteous and the wicked. But the oil cannot then be transferred to the vessels of those who have it not. Then shall be fulfilled the words of Christ: "Two women shall be grinding together; the one shall be taken, and the other left. Two men shall be in the field; the one shall be taken, and the other left." The righteous and the wicked are to be associated together in the work of life. But the Lord reads the character; He discerns who are obedient children, who respect and love His commandments.       Testimonies to Ministers and Gospel Workers p. 233-234

I never knew you

And while they went to buy, the bridegroom came; and they that were ready went in with him to 

the marriage: and the door was shut.

Afterward came also the other virgins, saying, Lord, Lord, open to us.

But he answered and said, Verily I say unto you, I know you not.

Watch therefore, for ye know neither the day nor the hour wherein the Son of man cometh.
Matthew 25:10-13 KJV

Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.

Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?

Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.

18A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.

Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.

Wherefore by their fruits ye shall know them.

Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.

Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?

And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.

Matthew 7:15-23. KJV

False wheat among the wheat

24 Another parable put he forth unto them, saying, The kingdom of heaven is likened unto a man which sowed good seed in his field:

25 But while men slept, his enemy came and sowed tares among the wheat, and went his way.

26 But when the blade was sprung up, and brought forth fruit, then appeared the tares also.

27 So the servants of the householder came and said unto him, Sir, didst not thou sow good seed in thy field? from whence then hath it tares?

28 He said unto them, An enemy hath done this. The servants said unto him, Wilt thou then that we go and gather them up?

29 But he said, Nay; lest while ye gather up the tares, ye root up also the wheat with them.

30 Let both grow together until the harvest: and in the time of harvest I will say to the reapers, Gather ye together first the tares, and bind them in bundles to burn them: but gather the wheat into my barn.

31 Another parable put he forth unto them, saying, The kingdom of heaven is like to a grain of mustard seed, which a man took, and sowed in his field:

32 Which indeed is the least of all seeds: but when it is grown, it is the greatest among herbs, and becometh a tree, so that the birds of the air come and lodge in the branches thereof.

33 Another parable spake he unto them; The kingdom of heaven is like unto leaven, which a woman took, and hid in three measures of meal, till the whole was leavened.

34 All these things spake Jesus unto the multitude in parables; and without a parable spake he not unto them:

35 That it might be fulfilled which was spoken by the prophet, saying, I will open my mouth in parables; I will utter things which have been kept secret from the foundation of the world.

36 Then Jesus sent the multitude away, and went into the house: and his disciples came unto him, saying, Declare unto us the parable of the tares of the field.

37 He answered and said unto them, He that soweth the good seed is the Son of man;

38 The field is the world; the good seed are the children of the kingdom; but the tares are the children of the wicked one;

39 The enemy that sowed them is the devil; the harvest is the end of the world; and the reapers are the angels.

40 As therefore the tares are gathered and burned in the fire; so shall it be in the end of this world.

41 The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend, and them which do iniquity;

42 And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth.

43 Then shall the righteous shine forth as the sun in the kingdom of their Father. Who hath ears to hear, let him hear.

Matthew 13:24-43 KJV

Darnel (Tare) usually grows in the same production zones as wheat and is considered a weed. The similarity between these two plants is so great that in some regions, darnel is referred to as "false wheat".^[1] It bears a close resemblance to wheat until the ear appears. The spikes of L. temulentum are more slender than those of wheat. The spikelets are oriented edgeways to the rachis and have only a single glume, while those of wheat are oriented with the flat side to the rachis and have two glumes. The wheat will also appear brown when ripe, whereas the darnel is black.^[2]

Darnel can be infected by an endophytic fungus of the genus Neotyphodium, and the endophyte-produced, insecticidal loline alkaloids were first isolated from this plant.^[3] The French word for darnel is ivraie (from Latin ebriacus, intoxicated), which expresses the drunken nausea from eating the infected plant, which can be fatal.^{[citation needed]} The French name echoes the scientific name, Latin temulentus "drunk."

Footnotes: 

1. Craig S. Keener, The Gospel of Matthew: A Socio-Rhetorical Commentary, Wm. B. Eerdmans Publishing, 2009 p.387

2.  Heinrich W.Guggenheimer, The Jerusalem Talmud,Vol. 1, Part 3, Walter de Gruyter, 2000 p.5

3. Schardl CL, Grossman RB, Nagabhyru P, Faulkner JR, Mallik UP (2007). "Loline alkaloids: currencies of mutualism". Phytochemistry 68 (7): 980–996. doi:10.1016/j.phytochem.2007.01.010. PMID 17346759.

Wikipedia