This week we receive one of the most iconic of mitzvot, commandments: the tzitzit. We put tassles on the corners of a four cornered garment and these tassles are to remind us of the commandments and of our service of and relationship to G-d. We're also told an interesting detail about the tzitzit, that they should have blue string as well as the background white. What does this colour mix symbolise?
The Gemara tells us that the blue of tzitzit is similar to the sea, which in turn reminds us of the sky, which itself reminds us of G-d's throne. The blue reminds us to keep mitzvot, to maintain a sense of our Jewishness, because it directly symbolises our connection with the divine. But why do we need the white? Why not have only blue?
A life of just the commandments, just our religious activities would not be possible or desirable. Hashem wants us to go out into the world and work and make it a better place. However, when we're doing that, we should never forget what we are and where we are coming from. The blue and the white wrap and around and through each other to remind us that when we're doing other things, we're still Jewish and when we're doing "Jewish" things, there is a broader world around us. They complement each other and we strive to be equally involved in both.