When you are driving along and come to a red light, when do you start to apply the brakes? In other words, when do you start to stop.
We all know that going through a red light is not only illegal, it’s dangerous.But you can’t just zoom up to a red light at full speed and then slam the brakes. There are other variables to consider: whether there are cars ahead of you or people in the cross walk; how fast you are going; whether the road is dry or icy; etc. All of that (and more) will affect when you begin to apply the brakes.
I’m finding that observing mitzvot (commandments) is very similar.