I am the door. If anyone enters in by me, he will be saved, and will go in and go out, and will find pasture.
We have entered into life accordingly Gospel through Christ (that is with faith received with repentance and conversion). As such we received salvation accordingly to faith in Christ.
Christ says that one who enters and is saved will also go in and go out. This means that we will go out from any particular mode of life (that is any law). Gospel is not an exception. During use it wears old like a law and the necessity to go out (to not follow Gospel like a law inscribed in stone anymore) arises.
This concerns not only Gospel but any law (a system of principles) according which we live. Any law wears old and we need to exit from it.
This verse ends with the words of Christ
and will find pasture. Thu means that to find a pasture (a blessing such as more money) we need to exit from the law (a system of principles) we lived before.
Read my book End of Gospel about how the life accordingly Gospel ends and we move up to the next level.