en_tn/jos/09/14.md

The Gibeonites succeed in deceiving the nation of Israel.

Joshua made peace with them and made a solemn promise secured with blood, to let them live. The leaders of Israel also made a vow to them

These two sentences are saying that the same thing occurred. Joshua, the leader of the nation of Israel, promised not to kill the Gibeonites. The leaders of the nation of Israel, likewise, made the same covenant. AT:"Joshua and the leaders of Israel made a blood covenant with the people of Gibeon." (See: rc://en/ta/man/translate/figs-parallelism)

a solemn promise secured with blood

This is a promise of blood for blood, or life for life that the people of Israel would not kill and was agreed to by an oath, using the name of Yahweh.

the people

Here this refers to the people of Israel. (See: rc://en/ta/man/translate/figs-metonymy)