Kiddushin 61B

למה לי? שמע מינה לתנאי כפול הוא דאתא.

Why do I need this extra phrase? Conclude from it that it comes to teach the requirement of a compound condition.

ורבי חנינא בן גמליאל אמר: אי לא כתב רחמנא ״בארץ כנען״, הוה אמינא ״ונאחזו בתככם״⁠ – בארץ גלעד, אבל ארץ כנען ⁠– כלל לא. ורבי מאיר? ״בתככם״⁠ – כל היכא דאית לכו משמע.

And R' Ḥanina ben Gamliel says: If God had not written: “In the land of Canaan,” I would say that the requirement: “They should receive a possession among you” (Numbers 32:30) is referring to the land of Gilead, i.e., this land must be shared with the other tribes. But they would not inherit in the land of Canaan at all. The Talmud asks: And how does R' Meir respond to this claim? He maintains that the expression: “Among you,” means anywhere that you have taken possession, including the land of Canaan. Therefore, the subsequent phrase “the land of Canaan” is superfluous and serves to teach that the condition must be doubled.

תניא: אמר רבי חנינא בן גמליאל: משל למה הדבר דומה ⁠– לאדם שהיה מחלק נכסיו לבניו, אמר: פלוני בני יירש שדה פלונית, ופלוני בני יירש שדה פלונית, ופלוני בני יתן מאתים זוז ויירש שדה פלונית, ואם לא יתן ⁠– יירש עם אחיו בשאר נכסים.

It is taught in a baraita with regard to this issue that R' Ḥanina ben Gamliel said: Hear a parable: To what is this matter, i.e., the condition of the children of Gad and Reuben, comparable? It is comparable to a person who was dividing up his property among his sons, and said: My son so-and-so should inherit such and such a field; and my son so-and-so should inherit such and such a field; and my son so-and-so should give 200 dinars and inherit such and such a field, and if he does not give the money he will inherit a part of the remainder of the property with his brothers.

מי גרם לו לירש עם אחיו בשאר נכסים ⁠– כפילו גרם לו.

What causes the last brother to inherit a part of the remainder of the property with his brothers? The father’s double formulation of the condition causes him to inherit in this manner. It was therefore necessary for the father to state both sides and explain what will happen if the third brother fails to give the money. Had the father not repeated the condition, upon failing to give the 200 dinars the son would not have received any portion of the property.