Rabbi Akiva was once asked to explain the entire Torah to someone as they stood on one foot. Rabbi Akiva immediately replied, "Thou shalt love thy neighbor as thyself. The rest is all commentary. Now go and study it."
Now certainly loving one's neighbor is important and beautiful, but is it really enough? Why did he not teach him the 10 commandments? I can stand on one foot for the two minutes it takes to recite them. And in the Ten Commandments, you also have faith in God. In fact, it's the first of them! Where is faith in God mentioned in the verse in Leviticus that Rabbi Akiva chooses to represent the whole Torah?
A different question may shed some light. The third of the commandments receives special mention in rabbinic literature, for they claim that when this commandment was given, the whole world trembled. "Thou shalt not take the Name of The Lord in vain." Why did this commandment, out of all of them, cause the whole world to tremble?
The Kli Yakar commentary compares this third commandment to lifting up a tree by the trunk. All of the branches will shake. God's Name is like the trunk of the tree. It is the interface between the Divine and the Earthly. When one utters it, one rises to connect to Hashem. When one utters it in order NOT to connect to Hashem, it is unsupported, unbalanced, disconnected. Everything shakes and becomes unstable. A world without God's connection to it is deeply unstable. And, by converse, if you see a society that is unstable, know that God's presence there is weak. The tree is shaking, the branches trembling.
An oh-so-true commentary I saw put things in very stark terms. Yes, the commandments forbidding killing, stealing, and so forth SHOULD be crystal clear, but are not. Why? Because of man's incredible ability to rationalize. He can find justification from WITHIN faith to kill, steal, rape, pillage and do whatever comes to his basest nature. He can use God's Name as his cover. We are killing the kuffar, the infidel, he will say.
To this, God says in the third commandment, "Thou shalt NOT take the Name of the Lord in vain!" You may not use Me as a justification for your evil actions. Thus, says this commentary, the whole world trembled, because now they know they would be culpable for all the murder and pillaging, rape and theft.
All of these things come from a disconnect with God, leading to a lethal disconnect from their fellow man. Ultimately, they disconnect from their own humanity and become the monsters we have seen on the news. It is clear and obvious and real.
Rabbi Akiva was interested in something else when he gave his answer of loving one's neighbor. He wanted to get people on the path to CONNECTION, to One-ness, to God. God is One, He desires all humanity to be as one. When Israel arrived at Sinai to receive the Torah, they arrived "as one man with one heart."
Character is the most determining factor in one's righteousness or lack thereof. Evil character, a hateful nature, gives one the impetus to disconnect from one's fellow, from one's self, from one's humanity. Good character, on the other hand, a loving nature, leads one to connect to one's fellow, to nature, to humanity, and, yes, to God. Be connected, says Rabbi Akiva, be a lover. Open your arms and your heart to others. When you do that, you will come to love yourself, and you will come to love God.
So Rabbi Akiva did not expressly mention faith, but he showed us the express path to it. The whole world shook when it heard about keeping God's Name connected. Imagine how wonderful the world WILL BE when we take God's Name, lift it up and connect it to all creation!