THE MEANING OF HOLINESS.

Holiness is the state or character of being holy, meaning cleanness or purity. The Hebrew Word 'holy' conveys the thought of separateness, exclusiveness, or sanctification to GOD, Who Is Holy; a state of being set aside to the service of GOD.
The quality of holiness belongs to GOD. In Exodus 28and 29, GOD gave this instructions: "Summon your brother Aaron and his sons, Nadab, Abihu, Eleazar, and Ithamar. SEPARATE them FROM the people of Israel, so that they may SERVE ME as Priests. MAKE priestly GARMENTS for AARON your brother, to PROVIDE him with DIGNITY and BEAUTY."  (28:1-2)
"WITH the blue, purple, and red WOOL they made the MAGNIFICENT GARMENTS which the PRIESTS were TO WEAR when THEY SERVED IN the HOLY PLACE." (39:1)
The prophecies in the Book of Zechariah deals with this sacred Holiness that involves the purification of GOD's people in order to rebuild GOD's temple.
The Prophet declared: "The Day when the LORD will sit in JUDGMENT is near." (1)
"Then Jerusalem will be looted, and the loot will be divided up before your eyes. The LORD will BRING all the nations together to make WAR on Jerusalem. The city will be taken, the houses looted, and the women raped. Half of the people will go into exile, but the rest of them will not be taken away from the city." (2)
"Then the LORD will GO OUT and FIGHT against those NATIONS, as HE has FOUGHT in times PAST." (3) "At that time HE will stand on the MOUNT of OLIVES, to the East of Jerusalem. Then the Mount of Olives will BE SPLIT in two from East to West BY al large VALLEY. One HALF of the Mountain will MOVE Northward, and the other HALF Southward."(4) "You will ESCAPE through this Valley that divides the Mountain in two. You will FLEE as your ancestors did when the earthquake struck in the time of King Uzziah of Judah." (5)
"The LORD my GOD will come, bringing all the angels with HIM. When that TIME COMES, there will no longer be cold or frost, nor ant darkness. There WILL ALWAYS BE daytime, even at night.
When this will happen is KNOWN ONLY TO the LORD." (6-7)
"When THAT DAY comes, FRESH WATER will flow from Jerusalem, half of it to the Dead Sea and the other half to the Mediterranean. It will flow all year long, in the dry season as well as the wet."(8)
"The the LORD will BE KING OVER all the EARTH; everyone will worship HIM AS GOD and KNOW HIM BY the SAME NAME." (9)
"The whole region, from Geba in the North to Rimmon in the South, will be made level. Jerusalem will tower above the land around it; the city will reach from the Benjamin Gate to the Corner Gate, where there had been an earlier Gate, and from the Tower of Hananel to the royal wine presses."(10)
"The people will live there in safety, no longer threatened by destruction." (11)
"The LORD will bring a terrible disease on all the nations that make war on Jerusalem. Their flesh will rot away while they are still alive; their eyes and tongues will rot away. At the same time the LORD will make them so confused and afraid that everyone will seize the man next to him and attack him."
"The men of Judah will fight to defend Jerusalem. They will take as loot the wealth of all the nations -gold, silver, and clothing in great abundance." "A terrible disease will also fall on the horses, the mules, the camels, and the donkeys -on all the animals in the camps of the enemy." (12-16)
"Then ALL OF  the SURVIVORS from the nations that have attacked Jerusalem will go there each year to worship the LORD ALMIGHTY as KING and to celebrate the Festival of Shelters. If any nation refuses to go and worship the LORD ALMIGHTY as KING, then rain will not fall on their land. It the Egyptians refuse to celebrate the Festival of Shelters, then they will be struck by the same disease that the LORD will send on every nation that refuses to go. This will be the punishment that will fall on Egypt and on all other nations if they do not celebrate the Festival of Shelters." (17-19)
"At that TIME even the harness bells of the horses will be inscribed with the Words "DEDICATED TO THE LORD." The cooking pots in the Temple will be as sacred as the bowls before the Altar."
"Every cooking pot in Jerusalem and in all Judah will be SET APART for use in the worship of the LORD ALMIGHTY. The people who offer sacrifices will use them for boiling the meat of the sacrifices."  "When the TIME comes, there will no longer be any merchant in the Temple of the LORD ALMIGHTY. (20-21)
The Israelites were frequently reminded that GOD is the SOURCE of all HOLINESS as they observed the WORDS "HOLINESS BELONGS TO GOD" that were engraved on the shining gold plate of the High Priest's turban. This plate was called "the Holy Sign of Dedication," showing that the High Priest was set apart to a service of special Holiness.
In Moses' victory song after the deliverance through the Red Sea, Israel sang: "WHO among the gods is like YOU, O GOD? WHO is like YOU, proving Yourself MIGHTY IN HOLINESS? (Exodus 15 :11; 1Samuel 2:2). As an added GUARANTEE of the CARRYING OUT of HIS WORD, GOD has even SWORN BY HIS HOLINESS. (Amos 4:2)
GOD"S Name is sacred and HIS NAME is to be held as HOLY, sanctified ABOVE ALL others (Mt 6:9).  Disrespect for HIS NAME merits the punishment of death (Lev 24:10-16,23; Num 15:30).
Since GOD is the ORIGINATOR of all RIGHTEOUS PRINCIPLES and LAWS (Jas 4:12)  and is the basis of all Holiness, any person or thing that is Holy becomes so because of the relationship with GOD and His Worship. One cannot have UNDERSTANDING or WISDOM unless he has KNOWLEDGE of the MOST HOLY ONE. (Prov 9:10) GOD can be worshiped only in Holiness. One claiming to worship HIM but practicing uncleanness is disgusting in GOD's SIGHT (Prov 21:27).
When GOD foretold that HE would make THE WAY CLEAR for His People to RETURN to Jerusalem from the exile, GOD said: "The WAY of HOLINESS it will BE CALLED. The unclean one will not pass over it"(Isa 35:8).
The HOLY SPIRIT operating on a person is an active force for Holiness or cleanness. Any unclean or wrong practice constitutes a resisting or grieving of that Spirit (Eph 4:30). Though impersonal in itself, the HOLY SPIRIT is expressive of GOD's Holy Personality and therefore can be grieved or made to feel hurt and this may result in GOD's changing into an enemy of the rebellious one (Isa 63:10).
A person grieving the HOLY SPIRIT may go so far as to blaspheme against it, which JESUS CHRIST said about that specific sin, that it will not be forgiven in the present system of things nor in that to come. (Mt 12:31, 32; Mr 3:28-30)