Genesis 43:32And they set on for him by himself, and for them by themselves, and for the Egyptians, which did eat with him, by themselves: because the Egyptians might not eat bread with the Hebrews; for that is an abomination unto the Egyptians.
See All..., in reference to Joseph eating with his brethren before they knew who he was, states, "And they set on for him by himself, and for them by themselves, and for the Egyptians, which did eat with him, by themselves: because the Egyptians might not eat bread with the Hebrews; for that is an abomination unto the Egyptians." In this verse we see three categories of people--all of whom were unable to eat (or fellowship) with the others.

1. The Egyptians, who are a picture of the lost.
2. The brothers of Joseph, who are a picture of believers who are out of fellowship with God. They had sold Joseph into slavery but had never repented of their deed.
3. Joseph, a picture of the believer in right fellowship with God.

Please note that the believer who is right with God cannot fully fellowship with the believers who are in rebellion. However, later, when Joseph's brothers confess their sin against him and repent, they are able to join in full fellowship. We often classify people as belonging to one of only two groups--the saved or the lost. However, this threefold division is also clear in scripture. Consider these titles from 1Corinthians.

1. The natural man (1Corinthians 2:14But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned.
   See All...) corresponds to the lost man; the person who is what he is by natural birth.
2. The carnal man (1Corinthians 3:1And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ.
   See All..., 3, 4) corresponds to the believer who is out of right fellowship with God.
3. The spiritual man (1Corinthians 2:13Which things also we speak, not in the words which man's wisdom teacheth, but which the Holy Ghost teacheth; comparing spiritual things with spiritual.
   See All..., 15; 3:1A prayer of Habakkuk the prophet upon Shigionoth.
   See All...) corresponds to the believer who is in a right relationship with God.

This is also seen in the stages of deliverance experienced by the Israelites when God brought them out of Egypt.

1. In Egypt - they were a picture of the lost
2. In the wilderness - they were a picture of the un-surrendered believer
3. In the Promised Land - they were a picture of the mature or spiritual believer

The question is, where are you? Are you lost in Egypt? Then you need to trust in Christ as your personal Saviour. Are you wandering in the wilderness? Then you need to give yourself entirely to God.