That is a portion of John 10:9 which reads:

“I am the door. If anyone enters by me, he will be saved and will go in and out and find pasture.”

Very recently I was told that the ‘going in and out’ in the passage refers to the possibility of a believer (a sheep) losing salvation. Since I had never heard the argument for losing one’s salvation from that verse, I was puzzled. 

Here is what I think is the argument:

If the sheepfold represents the Kingdom of God, the “going and out” refers to going in and out of the Kingdom of God. If you choose to go in and out of the sheepfold, as sheep do in the normal course of being sheep, You are entering the Kingdom of God and leaving the Kingdom of God. in other words, The context of the passage has to do with sheep, sheepfolds, good shepherds, and wolves.

Does the sheepfold represent the Kingdom of God, and Jesus  the and only entrance into the Kingdom? Most certainly it does! That settled, what does it mean that the sheep who have entered through the proper door ‘going in and out’ mean?  Jesus’ immediate listeners would probably have known exactly what it means,, especially if they were shepherds.

One of the many commentaries I read concerning the ‘going in and out and finding pasture’ explained it this way:

“The fold will ever be open to him who enters by the Door. He will have perfect freedom to enter, whenever storm or danger or night approaches. He will lead out and find pasture for his flock. In the devotion of his service, and in communion with God, he will daily have an increasing knowledge of truths new and old, and the truths which he learns he will give as food for the souls of men.”

Another put it this way:

“and shall go in and out and find pasture—in, as to a place of safety and repose; out, as to "green pastures and still waters" (Ps 23:2) for nourishment and refreshing,”

I especially like the reference to the 23d Psalm. It’s perfect! Having read other commentaries, all of which confirmed my initial thoughts on the matter, I will be so bold to assert that whatever John 10:9 is about, it’s NOT about losing one’s salvation!

Have a great day and a great weekend!