Here's the key:

* Earth spins on its axis, completing a rotation roughly every 24 hours. This is why we have day and night.

* The moon also spins on its axis, but it takes about 27.3 days to complete one rotation. This is the same amount of time it takes the moon to orbit the Earth.

Because of this synchronized rotation and orbit, we always see the same side of the moon. It's not that the moon doesn't spin, it's that its spin is perfectly aligned with its orbit.

This phenomenon is called tidal locking. It's caused by the gravitational pull between the Earth and the moon, which has slowed the moon's rotation over time.