Hebrews 9:27

Hebrews 9:27. In the end of the world hath he appeared to put away sin by the sacrifice of himself.

The Levitical priests continually repeated their sacrifice, for it was not effectual when offered only once; but our great High Priest has once for all presented a sacrifice which has made a full atonement for all his people’s sins, and there is therefore no need for it to be repeated.

Hebrews 9:27. And as it is appointed unto men once to die,

Notice how the apostle continues to introduce that important little key-word "once."