[And a cassis/helmet of brass, וְכ֤וֹבַע נְחֹ֙שֶׁת֙] And a galea/helmet of brass (Montanus, Pagnine, Jonathan, Syriac, Arabic), or of iron (Vatablus). By the name of brass is understood every sort of metal: and so in this place brass is taken for iron (certain interpreters in Lyra). Below it is written קוֹבַע, with a ק (Malvenda).
[And with a coat of mail hamata, with hooks (similarly the Septuagint)] But it is to be read squamata, with scales (Lapide).
[וְשִׁרְי֥וֹן קַשְׂקַשִּׂ֖ים] And a coat of mail with scales (Munster, Pagnine, Tigurinus, Junius and Tremellius, Vatablus in the Tigurinus Notes, Mariana), a breastplate of iron (or brass [Vatablus]) plates connected scale-by-scale (Menochius, Tirinus, similarly Lyra, Vatablus). Having scales after the likeness of fish, enclosed in such a way that no gap was among them (Rabbis in Dieu). Thus in Virgil’s Æneid 11 concerning Turnus, already dressed in his gleaming breastplate, he was bristling with bronze scales… (Malvenda). The ancients expressly write that the breastplates of the armored horsemen (whom the Persiansns call clibanarios, clad in mail) were made out of scales or plates, lest motion be impeded. Plates of brass (says Heliodorus) and iron of a palm’s width, on each side leading into a quadrangular form, fitting one upon another unto the extremes of the sides (in such a way that the superior always crosses over the inferior, and is contiguous with the one lying next to it, in a continuous series), and connecting its weaving with seams under the joints, make a certain scaled tunic (Bochart’s Sacred Geography “Phœnicia” 3:13:217). קַשְׂקֶשֶׂת/scale is formed from קָשָׁה, to be hard/sharp, although the latter is written with a שׁ/Schin/sh, the former with a שׂ/Sin/s (Bochart’s A Sacred Catalogue of Animals 1:1:6:38).
[The weight of his coat of mail was five thousand shekels (thus all interpreters)] A Shekel was of a half ounce in weight (Menochius, Tirinus, Malvenda, Hostus). Thus the weight was two hundred and eight Roman pounds (Menochius, Tirinus); or one hundred and fifty-six Zygostatic pounds (which are of sixteen ounces) with a quarter (Hostus’ Concerning the Duel of David and Goliath 5:79). Thus this weight appears too great to be believed. Therefore, perhaps these were lesser shekels (Mariana). They are here called shekels of brass: afterwards mention is made of shekels of iron, perhaps because the one was the weight of brass, the other of iron (Martyr). The shekel was twofold; 1. a greater, or sacred, which was containing half an ounce, or four drachmas: 2. a lesser, or prophane, lesser by half; it was containing a quarter part of an ounce (Martyr, Sanchez, Waser’s Concerning the Ancient Measurements of the Hebrews 2:9, Dieu). Four common shekels make an ounce; thus it was containing one thousand, two hundred and fifty ounces, that is, seventy-eight pounts with two ounces (Dutch).
Five thousand shekels of brass: The common shekel contained only a fourth part of an ounce; and so five thousand shekels made one thousand, two hundred and fifty ounces, which make exactly seventy-eighy pounds; which weight is not unsuitable to a man of such vast greatness and strength, as his height speaks him to be.
[And greaves of brass on his legs (thus the Septuagint, Munster, Tirinus, Strigelius, Syriac), וּמִצְחַ֥ת נְחֹ֖שֶׁת עַל־רַגְלָ֑יו] A frontlet of brass upon his feet (Montanus). The greaves are called a frontlet, because after the likeness of a frontlet they were of a plate (Mariana); or because they had the similitude of frontlets (Vatablus); or because, just as the forehead covers the anterior part of the head, so greaves cover the anterior part of the leges (Piscator). Broad plates of iron, or of steel (Vatablus), plates of brass (Pagnine, Munster), greaves of steel (Piscator), greaves of iron (Junius and Tremellius), or of steel (Tigurinus), were upon his feet (Junius and Tremellius, Pagnine), that is, they were protecting his legs in such a way that they were covering even his feet (Vatablus). Others thus: And a visor, or frontlet, towards his feet, because a certain plate came down from the crown of the helmet, covering the nose, and extending downwards unto the throat towards the feet, just as it was wont to be done in the case of ancient helmets (Lyra).
[And a target was covering his shoulders] Or between his shoulders (thus the Septuagint, Pagnine, Montanus, Tigurinus, Munster, Vatablus), understanding, was (Tigurinus). His shoulders were covered by a brass target: for that helmet was having a certain appendage that was sent down to the shoulders: or he had this in the place of a target; for it signifies that part which protects the back; that is, He was protected from the rear to best advantage (Vatablus). It was covering his shoulders, hung between the shoulders when he was not being fought, to be recalled to his breast in a time of conflict (Menochius out of Sanchez). [Others render כִּידוֹן otherwise.] For this כִּידוֹן is expressly distinguished from his target, of which there is a treatment in the following verse [on which see the things noted]. To some it was a sort of protective shoulder cover, or an iron ἐπιτραχήλιον, neck-piece, whereby either the shoulders or neck was defended from blows: thus Kimchi, Rabbi Salomon, and Rabbi Levi. These were preceded by the Chaldean interpreter, to whom כִּידוֹן/cidon was a brass shield projecting from the helmet, brought out between his shoulders; where in the place of מחפא, a covering, it is incorrectly read in the Chaldean מסחפא, and in Kimchi מחצפא, terms indicating nothing, in the explanation of which Lexicographers labor in vain. And they gather that a כִּידוֹן/cidon is a protective shoulder cover from this, that Goliath was bearing that between his shoulders; although from these words it is rather concluded not to have been a protective shoulder cover; for such is not between, but upon, the shoulders; I would not say that Goliath did not need a protective shoulder cover, because he was wearing a coat of mail; but a coat of mail does cover the shoulders. Moreover, out of verse 45, thou comest to me with a sword, and with a spear, וּבְכִידוֹן, and with a chidon; all things considered it is gathered that a cidon was a certain sort of weapon equally with the sword and spear. Josephus thus expressed this passage, but the spear was not a light burden of the right hand, but he was carrying it upon his shoulders. There is agreement among interpreters that the חֲנִית is a spear; and, that the כִּידוֹן/cidon is a short dart, is to be gathered from this, that it was carried, hung between the shoulders: For thus the Hebrew words have it, and a כִּידוֹן/cidon of brass between his shoulders, from which it was hanging. Therefore, to me it is most persuasive that the כִּידוֹן/cidon is a shaft, or javelin, or another similar sort of dart (Bochart’s A Sacred Catalogue of Animals 1:2:8:136). It is translated javelin (Castalio), spear (Josephus in Bochart’s A Sacred Catalogue of Animals). By כִּידוֹן/cidon they think to be signified רוֹמַח, javelin or spear. Others think it to be a collar, whereby the nakedness of the neck is protected (Munster). Others translate it club, or ball, of which they make use to capture and to strike. Others: arrow, dart. We: long spear, or German spear (Malvenda). Concerning the word כִּידוֹן/cidon see on Joshua 8 (Malvenda). But Kimchi says that כִּידוֹן/cidon here is not a javelin, as in Joshua 8; but, although it agrees in sound, it differs in signification (Bochart’s A Sacred Catalogue of Animals 1:2:8:136).
 Hebrew: וְכ֤וֹבַע נְחֹ֙שֶׁת֙ עַל־רֹאשׁ֔וֹ וְשִׁרְי֥וֹן קַשְׂקַשִּׂ֖ים ה֣וּא לָב֑וּשׁ וּמִשְׁקַל֙ הַשִּׁרְי֔וֹן חֲמֵשֶׁת־אֲלָפִ֥ים שְׁקָלִ֖ים נְחֹֽשֶֽׁת׃  Hebrew: לָבוּשׁ.  1 Samuel 17:38: “And Saul armed David with his armour, and he put an helmet of brass (ק֥וֹבַע נְחֹ֖שֶׁת) upon his head; also he armed him with a coat of mail.”  A Roman Pound was of twelve ounces.  That is, pertaining to the clerk of a market or weights.  Gasper Waser (1565-1625) was a minister, and a philologist specializing in Oriental languages. He was Professor of Hebrew (1596), and later of Greek (1607), at Zurich, and was eventually promoted to the chair of theology (1611). De Antiquis Mensuris Hebræorum.  Hebrew: וּמִצְחַ֥ת נְחֹ֖שֶׁת עַל־רַגְלָ֑יו וְכִיד֥וֹן נְחֹ֖שֶׁת בֵּ֥ין כְּתֵפָֽיו׃  Hebrew: וְכִידוֹן. מֵצַח signifies forehead.  Although little is known about the life of Levi ben Gershon, also known as Gersonides and Ralbag (1288-1344), his interests included, not only Biblical and Talmudic interpretation, but also philosophy, science, and mathematics.  Joshua 8:18: “And the Lord said unto Joshua, Stretch out the spear (בַּכִּידוֹן) that is in thy hand toward Ai; for I will give it into thine hand. And Joshua stretched out the spear (בַּכִּידוֹן) that he had in his hand toward the city.”