The Moon takes the same time to spin once on its axis as it does to complete an orbit around Earth. That time is about 27.3 days. The result: it always shows the same side to us. Not coincidence, the end product of billions of years of gravitational friction.
When the Moon formed, it spun much faster than today. Because its body isn't perfectly spherical (the side facing Earth is slightly more elongated), Earth's gravity pulls on that "bulge" and tries to align it with the line connecting the two bodies.
If the Moon spins faster than its orbit, the bulge runs ahead and gravity pulls it back, slowing the rotation. If it spins slower, the bulge runs behind and gravity pulls forward, accelerating it. Either way, the system converges to a state where rotation and orbit match. That's tidal locking.
The Moon reached that state probably more than 4 billion years ago. For it to spin up again or stop spinning, you'd need a major collision.
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