Occurrences in the Bible
The English word "white" or those related to this color ("whiter," "whited," etc.) are found 79 times in 70 King James Bible verses. They are found the most in Leviticus (20 times) followed by Revelation (19) and then Genesis (5). Thirty-one of this color's 79 occurrences are in the New Testament.
Not only is white mentioned the most of all Biblical colors, it is also derived from the most words! Thirteen Hebrew and one Aramaic word are used in the Old Testament for "white," "whiter," "white as snow," and so on.
In the New Testament, there are six distinct ways to specify something is white (e.g. "whited") for a Biblical total of twenty. This is the most for any color, as runner-up black is derived from 14 original language words.
Old Testament Usage
The word translated twenty-nine times as "white" is laban (or laben, #H3836). It is derived from the related word laben (#H3835) which itself is used five times for this color and its variation "whiter."
Purge me with hyssop, and I shall be clean: wash me, and I shall be whiter (laban, #H3835) than snow. (Psalm 51:7, KJV).
Come now, and let us reason together, saith the Lord: though your sins be as scarlet, they shall be as white (laban, #H3835) as snow; though they be red like crimson, they shall be as wool. (Isaiah 1:18, KJV).
The Hebrew chur (#H2353) is used twice in reference to cloth that was white (Esther 1:6, 8:15). Sheleg (#H7950) is also found twice to designate something white as snow (Numbers 12:10, 2Kings 5:27). In Esther 1:6 we find two mentions of the color.
Where were white (chur, #H2353), green, and blue, hangings, fastened with cords of fine linen and purple to silver rings and pillars of marble: the beds were of gold and silver, upon a pavement of red, and blue, and white (dar, #H1858, meaning white as a pearl), and black, marble. (Esther 1:6, KJV).
There are several other Hebrew words, and one that is Aramaic (chivvar, #H2358, Daniel 7:9), whose meaning is more descriptive. Genesis 40:16 refers to white in relation to bread (choriy, #H2751) while Job 6:6 mentions it in regard to an egg (riyr, #H7388). Psalm 68:14 uses a word for the color in relation to snow (shalag, #H7949) while 2Chronicles 5:12 uses it based on linen that is bleached (buts, #H948).
New Testament Usage
In the New Testament, the Greek word leukos (#G3022) is translated as "white" in the KJV 24 times. Koniao (#G2867) is rendered "whited" twice (Matthew 23:27, Acts 23:3) while leukaino (#G3021) is translated to make something this color in Mark 9:3 and Revelation 7:14.
The Greek lampros (#G2986) is used to reference white linen in Revelation 15:6. We then have the combination stole leukos (#G4749 and #G3022) to specify a long white garment in Mark 16:5. The last combination used is leukaino hautou (#G3021 and #G848) to state something was made white (Revelation 7:14).
Background
White has an HTML hex code of #FFFFFF. This color is seen by the human eye when all wavelengths of the visible spectrum combine. Unlike colors with hue, white is considered achromatic.
Red, green and blue (RGB) are considered primary colors for displaying images on electronic devices such as televisions, computer screens and smartphones. When these three are mixed together they produce a white light.
White pigments, in the past, have been derived from lead, lime, titanium dioxide, and zinc oxide. Lead white, a basic lead carbonate that is toxic, was also used anciently to generate this color.
Biblical Symbolism
White, in the Bible, symbolizes purity, righteousness, virtue and perfection.
I beheld till the thrones were cast down, and the Ancient of days did sit, whose garment was white as snow, and the hair of his head like the pure wool . . . (Daniel 7:9, KJV).
And He (Jesus) was transfigured before them; and His face shined as the sun, and His garments became white as the light. (Matthew 17:2, HBFV).
His head and his hairs were white like wool, as white as snow; and his eyes were as a flame of fire (Revelation 1:14, KJV).
God promises to forgive all those who repent and seek to do his will. He then will fulfill, for each person, His great purpose by making them permanently and eternally white (perfect in character) through trials and overcoming (see Matthew 5:48).
"Come now, and let us reason together," says the Lord. "Though your sins are as scarlet, they shall be as white as snow; though they are red like crimson, they shall be like wool." (Isaiah 1:18, HBFV).
And some of them of understanding shall fall, to try them, and to purge, and to make them white, even to the time of the end: because it is yet for a time appointed.
Many shall be purified, and made white, and tried; but the wicked shall do wickedly: and none of the wicked shall understand; but the wise shall understand (Daniel 11:35, 12:10, KJV).
The one who overcomes shall be clothed in white garments (Revelation 3:5, HBFV, see also 3:4, 18, 6:11, 7:9 - 14, 19:14).
The marriage supper of the Lamb is a time, yet future, when all the resurrected saints will appear before God and Jesus Christ. This supernatural supper will be a celebration for all those made white (permanently righteous) and brought into spiritual union with their Creator.
"Let us be glad and rejoice, and give honor to him: for the marriage of the Lamb is come, and his wife hath made herself ready."
And to her was granted that she should be arrayed in fine linen, clean and white: for the fine linen is the righteousness of saints. (Revelation 19:7 - 8, KJV).
A Unique Usage
In one unique prophetic case the color white is used to symbolize something completely opposite to righteousness.
And I looked, and behold, there was a white horse; and the one who was sitting on it had a bow, and a crown was given to him; and he went out conquering, and to conquer (Revelation 6:2, HBFV).
The above horse is the first of four horsemen of the apocalypse (Revelation 6:1 - 8). They herald manifold calamities to come upon the earth. As such, this first horse does NOT symbolize Jesus as his appearance and personal intervention on earth comes at a later time!
One of Satan's primary tactics is to lead people astray by appearing to be "an angel of light" who speaks the truth (2Corinthians 11:13 - 14). He is, however, the father of deception and lies, and a master counterfeiter.
God, in the end time, will allow great deception to "conquer," under the pretense of being the truth, all humans who refuse to repent (see Revelation 13). Jesus' true appearance on earth, on a white horse accompanied by all his immortal saints, will take place at the battle of Armageddon during his Second Coming!
And I saw heaven open; and behold, a white horse; and He Who sat on it is called Faithful and True, and in righteousness He does judge and make war.
And His eyes were like a flame of fire, and on His head were many crowns; and He had a name written that no one knows except Him. And He was clothed with a garment dipped in blood; and His name is The Word of God . . .
And I saw the beast and the kings of the earth and their armies, gathered together to make war with Him Who sits on the horse, and with His army. (Revelation 19:11 - 13, 19, HBFV).
More Info on White
The tradition of white wedding dresses was popularized by the 1840 A.D. wedding of England's Queen Victoria.
What is labeled the Great White Throne Judgment takes place in the second resurrection. It is a time, after the Millennium has completed, where God resurrects all those who never had a full chance at salvation.
But the rest of the dead lived not again until the thousand years were finished. This is the first resurrection . . .
And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them. And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life . . . (Revelation 20:5, 11 - 12, KJV).
At this judgment God will graciously open the mind of all those resurrected to his truth, giving them the ability to repent of their sins and ultimately receive eternal life.