Eruvin 63B

וכתיב: ״נון בנו יהושע בנו״.

And it is written at the end of the list of the descendants of Ephraim: “Non his son, Joshua his son” (i Chronicles 7:27), which implies that Joshua himself had no children.

ופליגא דרבי אבא בר פפא, דאמר רבי אבא בר פפא: לא נענש יהושע אלא בשביל שביטל את ישראל לילה אחת מפריה ורביה.

And this tradition differs from the following statement of R' Abba bar Pappa, for R' Abba bar Pappa said: Joshua was punished to remain childless only because he had prevented the Jewish people from fulfilling the commandment of being fruitful and multiplying for one night. Therefore, he was punished measure-for-measure by not having children himself.

שנאמר: ״ויהי בהיות יהושע ביריחו וישא עיניו וירא וגו׳״, וכתיב: ״ויאמר (לו) כי אני שר צבא ה׳ עתה באתי וגו׳״.

As it is stated: “And it came to pass when Joshua was by Jericho that he lifted up his eyes and looked, and, behold, a man stood over against him with his sword drawn in his hand” (Joshua 5:13), and it is written further: “And he said: No, but I am captain of the host of YHWH, I am now come” (Joshua 5:14). The man, an angel, came to demand something of Joshua and to rebuke him.

אמר לו: אמש ביטלתם תמיד של בין הערבים, ועכשיו ביטלתם תלמוד תורה. על איזה מהן באת? אמר לו: ״עתה באתי״.

The angel said to him: Last night, due to your preparations for war, you neglected the daily evening offering, and now, tonight, you are neglecting Torah study. Joshua asked him: For which of these sins have you come specially to reprove me? He said to him: “I am now come,” i.e., the fact that I did not come last night, but waited until now, shows that the sin of neglecting Torah study is the more severe one.

מיד: ״וילך יהושע בלילה ההוא בתוך העמק״, ואמר רבי יוחנן: מלמד שהלך בעומקה של הלכה.

Joshua immediately acted to rectify the matter by deciding that he must devote more time to learning Torah, as it is stated: “And Joshua walked that night in the midst of the valley [ha’emek]” (Joshua 8:13). And R' Yoḥanan said: This teaches that he walked all night in the depth [be’omeka] of halakha, thereby atoning for his previous neglect of Torah study.