Pardon my French! The title to this post literally means "Holy Blue!" and is an outdated expletive in French. Please excuse me if I have offended any French readers sensibilities... but I couldn't resist!
You see my friend, Richard, pointed out that the colour blue is also associated with holiness. As this is an important point, I decided to write a new post rather than hide a response away in the comments section.
In my own studies into the significance of this colour, I found the same thing. Especially in relation to the holy things in the tabernacle.
When the camp is to set out, Aaron and his sons shall go in and take down the veil of the screen and cover the ark of the testimony with it. Then they shall put on it a covering of goatskin and spread on top of that a cloth all of blue, and shall put in its poles. (Nu 4:5-6)
Here the ark, the representation of the holy presence of God, was covered with a cloth of blue. If you read on, you discover that all the holy things were to be covered in blue when they were transported.
The writer to the Hebrews says that these items were just copies of the heavenly realities that are fulfilled in Christ. They are thus pieces of a heavenly reality made manifest on the earth.
Blue is therefore an appropriate colour for these holy things, for it is after all the colour of the heavens above. It symbolises something of heaven made present on the earth.
This adds an important significance to the "blue thread" of God's eternal purpose that runs all the way through Scripture: it is the Father's heart to make heaven manifest on the earth.
This is how Jesus taught us to pray - that his kingdom would come on earth as it is in heaven. This is the vision that Daniel interpreted - a rock cut out of a heavenly mountain that grew until it reproduced that same mountain on the earth.
This is not a contradiction of seeing blue as representing the word of God, but it does align it (as I thought) more with the prophetic ministry of the word, rather than the teaching ministry. For it is the essence of prophetic ministry to see into the realities that are in heaven and lay hold of them, bringing them into the here and now.
Indeed the concepts of heavenly holiness, the word of God, and the river seem to be closely linked - not just by colour-coincidence...
Husbands, love your wives, just as Christ loved the church and gave himself up for her to make her holy, cleansing her by the washing with water through the word, and to present her to himself as a radiant church, without stain or wrinkle or any other blemish, but holy and blameless. (Eph 5:25-27 NIV)
Perhaps this also is the significance of the tassels of blue on the corners of the robes. As we walk in line with the word of God, with every step we take, the colour of heaven is touching the earth.