Before being accepted into the Fremen haven of Sietch Tabr, Paul must prove himself worthy. What is his test?

Paul proves himself to the Fremen by fighting Jamis to the death.

After Paul and Lady Jessica survive the journey across the desert, they encounter Stilgar's Fremen troop. Paul earns respect by using Bene Gesserit combat training, but Jamis distrusts the newcomers and challenges him. Their confrontation becomes a formal Fremen duel rather than a sparring match: neither fighter is expected to yield, and the contest ends only when one dies.

Paul wins the crysknife duel, killing Jamis. The victory helps establish him within the Fremen community, but it is not a simple triumph. Paul has foreseen Jamis in dreams and hesitates because he has never killed a man in this way before. Fremen custom then requires Paul to assume responsibility for Jamis's wife, Harah, and her children.

Readers sometimes confuse this duel with Paul's earlier combat demonstrations or with the events of the recent films, which rearrange and expand parts of the encounter. In Herbert's novel, the fight with Jamis is the decisive ritual that proves Paul's ability to survive under Fremen law.