In the Bible what is the greatest of all virtues?

Throughout The Bible, true humility is revealed to be the greatest virtue. Without it, other "virtues" are merely pretense (Luke 18:10-14).

2 Samuel 22:28 - You will save the humble people; But Your eyes are on the haughty, that You may bring them down.

Psalm 34:18 - The Lord is near to those who have a broken heart, And saves such as have a contrite spirit.

Proverbs 22:4 - By humility and the fear of the Lord Are riches and honor and life.

Isaiah 66:2 - For all those things My hand has made, And all those things exist," Says the Lord. "But on this one will I look: On him who is poor and of a contrite spirit, And who trembles at My Word."

Matthew 5:5 - Blessed are the meek, For they shall inherit the earth.

Luke 14:11 - "For whoever exalts himself will be humbled, and he who humbles himself will be exalted."

James 4:10 - Humble yourselves in the sight of the Lord, and He will lift you up.

1 Peter 5:5-7 - Likewise you younger people, submit yourselves to your elders. Yes, all of you be submissive to one another, and be clothed with humility, for "God resists the proud, But gives grace to the humble." Therefore humble yourselves under the mighty hand of God, that He may exalt you in due time, casting all your care upon Him, for He cares for you.

[Quotes from NKJV]