Or HaChaim on Numbers 14:8/אור החיים על במדבר י״ד:ח׳

1 אם חפץ בנו השם, "If G'd delights in us, etc." They were clever to present G'd's attitude to the Israelites as something still doubtful. They did this in order to have a chance to finish what they had to say without hostile interruptions. They succeeded in this and the people waited with their attempt to stone them until after they had completed their speech. This is where we ought to ask why the Israelites did not try and stone them already at the beginning of their words seeing they said nothing different in the course of their speech than what they had said at the beginning. We must therefore assume that the conditional word אם at the beginning of Joshua's words gave the people hope that he too would come up with something negative before concluding what he had to say.

3הוא זבת חלב ודבש, "it flows with milk and honey." They underlined their statement with the word הוא, to show that no other country could claim to match the excellence of the land of Canaan.