Why if you drink water directly from a river you'd be considered pagan?

Question

I once heard that one way to determine if a person were a pagan or Jewish was to see how the person drinks from a water reservoir (river/lake etc). If a person would hold the water with their hands and drink it from the hands then he/she was Jewish. If the water drunk directly from the river for example then it was a pagan.

I don't remember the exact details and where this is from but I heard it from Chabad people. Does anyone know what is the logic behind this method and where it is from? (Talmud or something else).

Answer 1

You're thinking of Shoftim 7:5

וַיּ֥וֹרֶד אֶת־הָעָ֖ם אֶל־הַמָּ֑יִם (ס) וַיֹּ֨אמֶר יְהוָ֜ה אֶל־גִּדְע֗וֹן כֹּ֣ל אֲשֶׁר־יָלֹק֩ בִּלְשׁוֹנ֨וֹ מִן־הַמַּ֜יִם כַּאֲשֶׁ֧ר יָלֹ֣ק הַכֶּ֗לֶב תַּצִּ֤יג אוֹתוֹ֙ לְבָ֔ד וְכֹ֛ל אֲשֶׁר־יִכְרַ֥ע עַל־בִּרְכָּ֖יו לִשְׁתּֽוֹת׃

So he took the troops down to the water. Then the LORD said to Gideon, “Set apart all those who lap up the water with their tongues like dogs, and all those who get down on their knees to drink.”

Rashi there says:

כל אשר ילוק בלשונו וגו' וכל אשר יכרע על ברכיו לשתות . תציג אותו לבד חוץ מסיעתך , כי הם לא ילכו עמך , שכך הם למודים לכרוע לפני עבודת גלולים :

All who lap up with their tongue, etc., and all who kneel on their knee to drink- Place him (the kneeler) alone, outside your band, for they will not come with you, for they have been taught to kneel in front of worship of idols.

Someone who bends down to drink shows he is used to idol worship, since his instinct is to bow. It doesn't appear to me that this is an all encompassing rule; rather something indicative at that specific time.

Note the Ralbag there gives a different explanation:

והנה לזאת הסבה גם כן לא רצה השם שישארו עמו זולתי המלקקים בידם אל פיהם כי זה מורה על חריצות וגבורה ואולם אשר כרעו על ברכיהם לשתות הם עצלים ורצה שישובו להם והנה במאמר הא' הגדיל מהם בעלי העבירות ורכי הלבב כי האיש הירא הוא ירא מעבירה שבידו כמו שביארו ז''ל בפרק משוח מלחמה והחרד הוא רך הלבב ובזה הענין השני הבדיל העצלים ולא השאיר כי אם הצדיקים והחרוצים והגבורי' והם היו שלש מאות איש לבד ובהם לבד החזיק כמו שצוה לו הש''י ע''י נביאו או בעצמו במראה הנבואה :

He says those who bent down to drink showed they were lazy and not mighty warriors.

Answer 2

The accepted answer misses the point a bit. The reason that these men were sent away was not that they were bad warriors or bad people.

Verse 2:

The LORD said to Gideon, “You have too many troops with you for Me to deliver Midian into their hands; Israel might claim for themselves the glory due to Me, thinking, ‘Our own hand has brought us victory.’

In verse 3, those that want to leave get to leave. Except there's still too many left: 10.000. Hence another sifting process is proposed in verse 4:

“There are still too many troops,” the LORD said to Gideon. “Take them down to the water and I will sift them for you there. Anyone of whom I tell you, ‘This one is to go with you,’ that one shall go with you; and anyone of whom I tell you, ‘This one is not to go with you,’ that one shall not go.”

This sifting process happens to be lapping vs. kneeling to drink. Only three hundred men lap: these get to go on. There is no reason to accuse the other 9.700 of idol worship: the reason they got sent away is stated in verse 2. Nowhere do they get classified as pagans afterwards. There is also no reason to state that "they must've been bad fighters", because following the reasoning in verse 2, it would make more sense to sent the good fighters away.

So to answer the question: Deciding by drinking if someone is a Jew or a pagan seems to be connected to the history of Gideon, but ultimately, to a rather uncalled-for interpretation of it.