The Hebrews were very familiar with the concept of an altar for it was there that thousands upon thousands of animals had been sacrificed as prescribed by the Old Covenant. It is almost certain that at the time the epistle to the Hebrews was written, animals were still being offered on the altar in Jerusalem at the temple precinct. Priests of the Levitical order stood daily at the altar repeatedly offering the same sacrifices which can never take away sins.
By contrast, there is another altar, the one upon which Jesus was offered, but only once. That altar is related to the cross upon which Jesus died to put away the sins of His people once for all. It is this altar to which the author refers when he writes, “We have an altar from which those who serve the tabernacle have no right to eat” (Heb. 13:10). There is a veiled warning here. His readers were Jewish people professing faith in Jesus Christ who were being tempted to go back to life and faith under the Old Covenant. By doing so they would forfeit the eternal benefits of Christ’s sacrifice for their sins.
The writer encourages these Jewish Christians to strengthen their commitment to Christ by going forth to Him outside the city of Jerusalem where He died (Heb.13:10-13). His sacrifice was not one of many Old Covenant sacrifices offered at the temple in Jerusalem. He died outside the gate of the city indicating that He had been rejected by Israel’s religious leaders, and that His sacrifice was not an Old Covenant sacrifice. The writer urged his readers to fully reject the Old Covenant system by going out of the city to bear with Jesus His reproach. We too must go out to Jesus and follow Him. We must be willing to suffer the ridicule, reproach and persecution that we may be called upon to endure as we follow Christ.