Midrasch zu Bamidbar 13:18

12 (Numb. 13:17) “When Moses sent them […] then he said unto them, ‘Go up here into the Negeb”: Why [first] into the Negeb? Because this is what the merchants do. They show the inferior goods first, and after that they show the best. (Vs. 18) “And you are to see what the land is like”: Three times did Moses tell them, “look over the Land of Israel” (in vss. 18, 19, 20). Why? The first, he said, “See what the land is.” He said to them, “Observe the land. There is land that raises strong men, and there is [land] that raises weaklings. There is also [land] that raises armies,¹⁷Gk.: Ochloi. and there is [land] that diminishes armies.” Thus did he charge them (in Numb. 13:18), “as for the people who dwell in it, are they mighty [or] weak?” (Numb. 13:19) “And what of the land, is it good or bad […]?” And how will you know about their strength? (Numb 13:19 cont.) “Are they in camps or in strongholds”: If they dwell in camps, they are mighty and depend upon their strength; but if they are in strongholds, they are weak and have fearful hearts. (Numb. 13:20) “And what of the land, Is it fertile [or lean]”: [How do we determine] whether its fruits are light or fat. He said to them, “Look at its stones and pebbles. If they are of flint, they are fat; and if they are of clay, they are lean.” (Ibid., cont.) “Now the time was the time for the first-fruits of the grapes”: From here you learn that [the month of] Tammuz is never without figs and grapes.