Perek 55 draws on a comparison between water and Torah. Let us expand and explain this connection.
The Midrash in Shir Hashirim compares Torah to water, saying that “Just as water only has a sweet taste if one is thirsty, so too Torah only has a sweet taste if one has a thirst for it.” There are two important points to glean from this Midrash. First, we see that Torah is supposed to be sweet, and second, this sweetness is directly related to our desire for Torah.
Even though on a basic level the Torah is sweet to anyone who merits understanding a little of its truth, on a deeper level, the sweetness of Torah is the extent to which the Torah affects us personally. Just as sweetness of taste occurs when the water enters our body, so too, the sweetness of Torah corresponds to how much one internalizes it. The true sweetness is in allowing Torah to seep into our very fibre to uplift us and make us better people, more connected to a Higher Source. This is why we ask that the Torah should be sweet for us, for learning Torah has the greatest power to perfect our character and connect us to Hashem. Unlike other mitzvos, the point of learning Torah can be completely missed – one who sees Torah as mere intellectual stimulation will not taste the true sweetness of Torah. The word “vehaarev” shares a root with the word ‘to mix’, for the sweetness of Torah is how much it has become mixed in to who we are. Thirst is a prerequisite for this sweetness, for the more one values something, the more one will ‘let that thing in’ to affect him. For example, one values and appreciates one’s parents much more than the mailman, and therefore one places trust in and generally allows one’s parents to shape one’s life more than the mailman. The same goes for Torah. The more we desire and value Torah, the more we allow ourselves to be exposed to and influenced by Torah.