One of the names by which we call HaShem is TSUR (צור). This name or attribute of God appears many times in the Tora and in the Tanakh, especially in the book of Psalms. The word TSUR referring to God is also used very often in our Tefila, for example at the end of the Amida (ה ‘צורי וגואלי).
In Hebrew, the word TSUR means “rock.” When God commanded Moshe to extract water from the rock, the Tora used two words interchangeably: one is sela ‘(סלע, or “stone” BeMidbar 20: 8) and the other is TSUR (or rock, Shemot 17: 6).
But why would the Tora call HaShem “rock”?
Three explanations. Not possible but complementary.
The first explanation, which seems to be the peshat (=the literal meaning) is brought by Maimonides in his More Nebukhim (1:16). HaRambam explains that the word TSUR is used metaphorically to refer to God as “our source”. As we all know, the Jews in the time of the Tanakh were experts in extracting, transporting and working the stone. The land of Israel is arid and mountainous, and stone extraction was one of the most common industries then. Until today there is a unique stone, famous in the world, called in Hebrew EBEN YERUSHALMI, the typical stone of Yerushalayim, the stones of the Kotel and the only stone that is permitted to be used when building in the Old city of Jerusalem.
People were very familiar with the origin of stones. All stones have ONE origin. The Rock (=rocky-mountain) or “quarry”. According to this beautiful Biblical metaphor, we are to HaShem what the stones are to the “rocky mountain”. This is what Yesha’ayahu (51:1) told explicitly the people of Israel, urging them to return to God: “Hear, you, who pursue righteousness and who seek HaShem; watch The Rock (צור חוצבתם) from which you were cut… . “.
According to this explanation, when we say TSUR in reference to HaShem we should think that He is The Source of all that exists. The Tora uses the word TSUR to refer to God as YOTSER, the Creator of everything and everyone (the beautiful word TSURI means: “My Creator”).
The second explanation (or application) of the word TSUR referring to Hashem can be learned from David HaMelekh. In Tehilim 144, for example, the Psalm in which David prays (or talks) to HaShem in the battlefield. In the first pasuq David calls HaShem TSURI. There, David is not referring to HaShem (only?) as his Creator but as his Protector. On the battlefield, the rock helps the soldier to hide and to protect himself from the arrows of the enemy. David HaMelekh understood that what protected him from the enemy’s weapons, and what made him invisible to the eyes of the enemy, was not a stone but HaShem, “his Rock”, his Protector.
Here TSUR is used to say that HaShem, beyond being our Creator, is also our Protector.