Perhaps you have opened a jar of chimichurri from the store and have only used a little. You can keep it in the fridge for two weeks but if you don’t intend to use it by then, you can freeze it. However, don’t freeze it in the jar as the jar may crack in the freezer. There’s no p[point in freezing a jar of unopened chimichurri as it has a long shelf life, much longer than chimichurri kept in the freezer.