Of the 2 contradictions listed above, the second one is easier to spot in the composite text as it now stands. After the men are dispatched and reconnoiter the land, Numbers 13:25 marks their return:
And they came back from scouting the land at the end of 40 days. And they went and came to Moses and to Aaron and to all the congregation of the children of Israel, to the wilderness of Paran, at Kadesh, and they brought back word to them and all the congregation and showed them the land’s fruit. (Num 13:25-26)
Thus in this account, the spies come to them, i.e., Moses, Aaron, and all the congregation, and speak to them of their mission. Yet look at what the following verse says.
And they told him and said, “We came to the land where you (s.) sent us…. (Num 13:27)
In this verse the men report back and speak to him, that is Moses, only. That is because there is no Aaron or congregation of the children of Israel—uniquely Priestly phrases—in the Yahwist version which has only Moses instructing the men and the men returning to Moses. Verses 25-26 are from the Priestly version of this story and were later spliced into the Yahwist story in between verses 24 and 27.
Likewise, although it is not explicitly stated in the text, the Yahwist version doesn’t specify a chieftain from each tribe to reconnoiter the land. This interest in chieftains—a uniquely Priestly term!—is unique to the Priestly source (see Numbers 1-4; #217, #218). This claim may somewhat be supported by noting that later in the Yahwist story, the men choose to select chiefs (a different Hebrew word than P’s chieftains) to go back to Egypt (14:4). Had there been chiefs already assigned one would imagine this wouldn’t have been necessary. Point of fact, there is just no interest in the tribes, genealogy of the tribes, number of the tribes, and the chieftains of the tribes in the Yahwist source. These are exclusively Priestly themes and interests.
At any event, if we separate the 2 version out, this is what we’re left with.
1And Yahweh spoke to Moses, saying: 2“Send men and let them scout the land of Canaan that I am giving to the children of Israel. You shall send one man for each tribe of his fathers, everyone of them a chieftain.” 3And Moses sent them from the wilderness of Paran according to Yahweh’s word. They were all men who were heads of the children of Israel.
4And these were their names: of the tribe of Reuben, Shammua the son of Zaccur. 5Of the tribe of Simeon, Shaphat the son of Hori. 6Of the tribe of Judah, Caleb the son of Jephunneh. 7Of the tribe of Issachar, Igal the son of Joseph. 8Of the tribe of Ephraim, Hoshea the son of Nun. 9Of the tribe of Benjamin, Palti the son of Raphu. 10Of the tribe of Zebulun, Gaddiel the son of Sodi. 11Of the tribe of Joseph, namely, of the tribe of Manasseh, Gaddi the son of Susi. 12Of the tribe of Dan, Ammiel the son of Gemalli. 13Of the tribe of Asher, Sethur the son of Michael. 14Of the tribe of Naphtali, Nahbi the son of Vophsi. 15Of the tribe of Gad, Geuel the son of Machi. 16These are the names of the men whom Moses sent to scout the land. And Moses called Hoshea the son of Nun Joshua.
17aAnd Moses sent them to scout the land of Canaan.
21And they went up and scouted the land from the wilderness of Zin to Rehob at the entrance of Hamath.
25And they came back from scouting the land at the end of 40 days. 26And they went and came to Moses and to Aaron and to all the congregation of the children of Israel, to the wilderness of Paran, at Kadesh, and they brought back word to them and all the congregation and showed them the land’s fruit. (continued at verse 32).
17bAnd he [Moses] said to them: “Go up there in the Negeb, and you shall go up the mountain 18and see the land, what it is; and the people that dwell therein, whether they are strong or weak, whether they are few or many; 19and what the land is that they dwell in, whether it is good or bad; and what cities they are that they dwell in, whether in camps, or in strongholds; 20and what the land is, whether it is fat or lean, whether there is wood therein, or not. And be of good courage, and bring of the fruit of the land.” And it was in the days of the first grapes.
22And they went up in the Negeb and came to Hebron; and Ahiman, Sheshai, and Talmai, the children of Anak, were there. (And Hebron was built seven years before Zoan in Egypt.) 23And they came to the Wadi Eshcol, and they cut a branch with one cluster of grapes from there, and they carried it upon a pole between two people—and some pomegranates and some figs. 24That place was called Wadi Eshcol on account of the cluster that the children of Israel cut from there.
27And they told him and said, “We came to the land where you sent us….
The original beginning of the Yahwist version looks as though it just opened with Moses commanding an unmentioned group of men to scout out the land of Judah alone (#234). The Priestly writer redrafted the account to have the reconnaissance mission explicitly stated as “the word of Yahweh.” And he also marked it with his interest in tribal organization and chieftains, as well as expanded the mission to include all the land of Canaan. Thus, while in the Yahwist version the unmentioned group of men return from the plains of Judah and report back to Moses alone, in the Priestly version the 12 chieftains return to Moses and Aaron, and the congregation, 40 days later after scouting out the entire land of Canaan as far north as Hamath.
As we have seen in numerous other entries, a later redactor decided to preserve both traditions, and cleverly in a cut-and-paste fashion.