Can you explain the color blue in the tzitzis?
The Torah instructs us to use the color blue, together with the color white, in the strings of the tzitzis. This color is called techeiles, and although some believe to have found the true source of the color (it must be taken from a sea creature called chillazon, which some have identified as the murex snail), the mainstream belief is that we are still unsure as to the precise hue and its source.
Some explain the significance of the color based on the word techeiles, which means “destiny.” The color blue is seen whenever we see ad infinitum (the sky therefore appears to be blue), and the tzitzis connects our physical clothing with the infinity of the spiritual: the destiny of man.
In a similar sense, the Talmud writes that the blue color on the string reminds a person of the sea, brining him to think of the sky, and the Throne of Glory.
[Concerning the Messiah, please see previous posts on the subject.]