Poole on 1 Samuel 7:12: Eben-ezer
Verse 12: Then Samuel (Gen. 28:18; 31:45; 35:14; Josh. 4:9; 24:26) took a stone, and set it between Mizpeh and Shen, and called the name of it (1 Sam. 4:1) Eben-ezer (that is, the stone of help), saying, Hitherto hath the LORD helped us.
[He brought a stone, etc.] To perpetuate the memory of the benefit received, and of the victory. Others did the same: Jacob, Genesis 28:18; 35:14; Moses, Exodus 24:4; Joshua, Joshua 4:8, 9. Question: Whether Samuel violated that law in Leviticus 26:1, ye shall not place an eminent stone…? Response: Not at all. 1. The law prohibited the erecting of a stone for worship, but not for other ends (certain interpreters in Mendoza). On the contrary: The erection of stones was prohibited, not only with the intention, but also with the danger, of worship (Mendoza). 2. A stone polished, painted, and marked was prohibited; not rude and unpolished, which by its appearance would tempt no one to worship (certain interpreters in Mendoza). 3. The truer response is, that Samuel enjoyed a divine privilege (Mendoza).
A stone; a rude, unpolished stone, which was not prohibited by that law, Leviticus 26:1, there being no danger of worshipping such a stone, and this being set up only as a monument of the victory.
[Between Mizpeh and Shen, וּבֵ֣ין הַשֵּׁ֔ן] [Some take it appellatively.] Between that boulder (Drusius, Junius and Tremellius), called eben-ezer, concerning which 1 Samuel 4:1 (Junius); tooth/projection (Piscator, Drusius, Munster). Thus the Hebrew language calls a projecting rock (Munster). The tooth/projection of rock; that is, a boulder (Munster). Between that tooth/ projection, which in verse 11 was called Beth-car (Malvenda). And between the ancient (Septuagint); they confound שֵׁן/shen/tooth with יָשֵׁן/old (Drusius). [To others it is a proper name.] Between Shina (Jonathan), Shen (Pagnine, Montanus, Vatablus); between Beth-jasan (Syriac, Arabic). It was a promontory, or part of cliff that was jutting out farther (Vatablus).
[The stone of help] The Greeks have, the stone of the helper. But helper is עוֹזֵר, not עֶזֶר/help (Drusius). The Pagans were erecting monuments, but to themselves; but Samuel erected this to God. He does not ascribe that victory to the stone; but, according to the nature of Sacraments, he attributes to the symbol what was proper to the matter itself (Martyr).
Eben-ezer; by which, compared with 1 Samuel 4:1, it appears that this victory was gained in or near the very same place where the Israelites received their former fatal loss.
[Hitherto, etc.] He indicates that this help was not unto the total overthrow of their enemies, but limited to certain events only. This was done, lest the people in victory should become haughty, and loosed from all fear. For it was better prudently to fear and to prepare, than rashly to presume and to exult (Mendoza).
Hitherto hath the Lord helped us; he hath begun to help us in some measure, though not completely to deliver us; by which wary expression he exciteth both their thankfulness for their mercy received, and their holy fear and care to please and serve the Lord, that he might proceed to help and deliver them more effectually.
 Hebrew: וַיִּקַּ֙ח שְׁמוּאֵ֜ל אֶ֣בֶן אַחַ֗ת וַיָּ֤שֶׂם בֵּֽין־הַמִּצְפָּה֙ וּבֵ֣ין הַשֵּׁ֔ן וַיִּקְרָ֥א אֶת־שְׁמָ֖הּ אֶ֣בֶן הָעָ֑זֶר וַיֹּאמַ֕ר עַד־הֵ֖נָּה עֲזָרָ֥נוּ יְהוָֽה׃  Hebrew: אֶ֣בֶן הָעָ֑זֶר. שֵׁן/shen signifies tooth.  Hebrew: אֶ֣בֶן הָעָ֑זֶר.