You're likely thinking of Newton's First Law of Motion, also known as the Law of Inertia. It states:

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Here's how it relates to velocity:

* Velocity is a vector quantity that describes both the speed and direction of an object.

* Newton's First Law explains that an object's velocity will remain constant unless a force acts on it.

Here's an example:

Imagine a ball sitting on a table. It's at rest, meaning its velocity is 0. If no one touches it, it will stay at rest.

Now, imagine that same ball is rolling across a frictionless surface. It will continue to roll at the same speed and in the same direction forever, because there's no force to stop it or change its path.

In short: Newton's First Law is about maintaining constant velocity. Objects won't change their velocity unless a force intervenes.