כל נשיא בהם. The principal meaning of the verse is as follows: you should take as the twelve representatives, one of each tribe, men whose heart was set on going on to the Holy Land. You should select volunteers, willing to act as spies. From among all these volunteers you are to select the ones who appear most suitable to you. Seeing that what was required were stout-hearted men, physically strong so that they could carry with them samples of the produce of the land, G’d did not mention them by name, as He had done when he appointed the 12 princes who were to be leaders of each tribe. G’d also appointed by name the next generation of such tribal princes, the ones who would enter the Holy Land together with their respective tribes.

כל נשיא בהם, the tone-sign under the word כל spells out its meaning. Each one of these 12 had volunteered for the assignment. In recognition of this he was accorded the title נשיא,“prince.” We encounter a similar meaning of the word כל in Psalms 8,7 כל שתה תחת רגליו, “laying “all” (the world) at his feet.”

ויקרא משה להושע בן נון יהושע, this does not mean that the people from then on called this man Joshua. It means that the man who had been referred to as Hosheah son of Nun in his father’s house was the one whom Moses now referred to as Joshua. The change had occurred already at the time when Moses appointed this man to be his personal valet. It was customary to change the names of people who were promoted in rank. We find this the first time when Pharaoh changed Joseph’s name to Tzofnat Paneach (Genesis 41,45) We find it again in Daniel 1,6 when Nevuchadnezzar’s chief officer changed Daniel’s name to Belteshazzar. This had been a reference to a Babylonian idol so named. The first time Joshua’s name had been changed was in Exodus 24,13.

וראיתם את הארץ מה היא, if, the first part of the country you encounter is wooded, mountainous, flat, cultivated, etc. This was necessary so that the army could plan what equipment was needed for the opening stages of the campaign. The people were convinced that G’d would give them the land of Canaan, but they anticipated that this would not be without efforts on their part. Even if there would not be actual fighting and casualties, at least they would have to prepare for this eventuality.

ומה הארץ אשר הוא יושב, seeing that the words ומה הארץ of which we said that they referred to the parts of the country which the invaders would face immediately, an area not populated, now the Torah refers to other parts of the land of Canaan which were fully populated. Hence the words:

בארץ אשר הם יושבים בה הטובה היא אם רעה, if the land produces ample harvests so that the invaders would be able to supply themselves with locally grown produce instead of bringing the food supply with them.

הבמחנים, whether the inhabitants live in open cities or in fortresses. All this kind of information was needed so that they would know to take with them the tools needed to lay siege to fortresses, for instance.

השמנה היא, to inform the Israelites on their return if the land was indeed “flowing with milk and honey,” as G’d had led them to believe.

והתחזקתם, give yourselves the appearance of self confident men, men who are not afraid of anything.

והימים ימי בכורי הענבים, the reason the Torah mentions this is because the spies brought with them a cluster of locally grown grapes.

ויבא עד חברון. The well known aggadic comment is widely perceived as the plain meaning of this verse, i.e. that the verse (in the singular, “he came”) refers to Calev of whom the Torah reports “to him I will give the land which he crossed on foot.” (Deuteronomy 1,36)

(2) BEFORE TZO'AN OF EGYPT. According to the plain sense, it was built before Tzo'an, and also, the older city is more important than the new city. For Israel were familiar with the importance of Tzo'an; it was necessary to say that the cities of Israel were more important. And also, because of its age, there giants there who were from the early generations.

ויהס, he silenced them by using his psychological insights.

מן הנפילים, the original ones of which the Torah had written that they lived in antediluvian times (Genesis 6,4)

כחגבים, anything low considers itself as like a grasshopper when compared to something much taller. We find proof of this in Isaiah 40,22 היושב על חוג הארץ ויושביה כחגבים, “compared to the One Who is enthroned above the vault of the earth views its inhabitants as if they were grasshopper.”