In the most common version of the Tree of Life, Chet connects Binah, Understanding, to Tipherah, Beauty. In the Ari's version, Chet connects Chesed, Mercy, to Tipherah. Connecting Binah, Chet represents the Understanding that we find in the balance of Tipherah. It isn't the pure Understanding of Binah, but it is balanced by the Wisdom of Chokmah. Chet bridges that gap between the power of Binah coming down the Pillar of Severity and the power of Chokmah coming down the Pillar of Mercy, by giving Understanding in the point of balance. In the Ari's version, Chet bridges the gap between Heaven and Earth, Kether and Malkuth, by bringing Mercy into the balancing point between them, Tipherah. As the number eight, Chet represents the eight people who were saved from the Flood, the bridge between the old world and the new. It is also the day after birth that circumcision occurs, which represents the covenant between G-d and Abraham, hence the Bridge between Abraham's old life and a life with G-d. Chet represents what is new, a new start after the completion of Zayin. A related word to Chet is חוט, chuwt. It has the same main letters as Chet, Chet and Tet, with a Vev between. It means a thread, cord, line, or string. In this sense, Chet binds the two worlds together, being the bridge between them. The Priests served in Israel as a Bridge between G-d and his people. Chet is the Priesthood, the servants of G-d. They were the bridge. We are the Bridge.
On the Western Tree, Chet connects Binah to Geburah, Judgement. It is Understanding being brought into Judgement to allow good decisions to be made. Before the Fool comes along, this is where you can find the Chariot. After the Fool is gone, Strength stands in Chet.
The Chariot in Chet is about duality coming together. Chet Bridges the barriors between male/female, life/death, good/evil. In Chet, the dualities become one, just as they do in the Chariot.
But the Chariot doesn't stay there. As it moves on, the Fool comes to Chet. Chet is the Bridge between the first part of the Fool's journey and what is to come. From here he passes into territory that is strange to him. He has moved past the physical persons he has been meeting to the symbolic persons beyond. In Chet, the Fool learns to make that transition, and climbs the Fence into a whole new world.
After the Fool has left, Strength stands in Chet. Strength stands in control of its inner strength, bringing Understanding into Judgement. It requires an inner Strength and a lot of Understanding to stand in judgement and believe in what you do. Strength is the power of G-d hovering over the physical, waiting for us to grab on with both hands. Strength can hold us.
Are you connected to G-d, or are you a Vev, floating free with no Zayin to connect to? The first step is to find that Bridge yourself. G-d is just out of reach, hovering just beyond what we see as reality. Reach out to G-d and he'll reach back. Bind yourself to him. Once you have a hold on the Other World, once G-d has caught your hand, you are no longer only in the land of the physical. You are no longer a Vev, but a Chet, with one leg on each side. You are now a Bridge. Now, you can help others cross. Reach out to them as G-d reached out to you, and draw them over. Open the gate in the Fence and allow people to cross over the Bridge, which is you.