Gesenius' Hebrew Grammar/163. Adversative and Exceptive Clauses
163a 1. After negative sentences (especially after prohibitions) the antithesis (but) is introduced by כִּי אִם, e.g. 1 S 819 and they said, Nay, but we will have a king over us; ψ 12, &c.; frequently also by כִּי alone, e.g. Gn 1815, 192, or even simply connected with וְ, Gn 175, וְהָיָה as perfect consecutive; 42:10; cf. Ex 518.
163b Rem. Sometimes the negation is only virtually contained in the preceding sentence, e.g. in the form of a rhetorical question (Mi 63 f.) or of conditions which are to be regarded as not having been fulfilled (Jb 3118); כִּי or כִּי אִם in such cases becomes equivalent to nay, rather.
163c 2. Exceptive clauses, depending on another sentence, are introduced by אֶ֫פֶס כִּי except that, and (again after negative sentences, see a above) כִּי אִם unless; especially כִּי אִם with the perfect (equivalent to unless previously) after imperfects which contain a declaration, e.g. Gn 3227 I will not let thee go, except thou hast previously blessed me; Lv 226, Is 5510, 656, Am 37, Ru 318. Finally, בִּלְתִּי אִם unless, Am 34 (with perfect after a rhetorical question), or simply בִּלְתִּי Gn 433 with a noun-clause, except your brother be with you; Is 104 after a rhetorical question, with a verbal-clause. 163d Rem. The principal statement, to which כִּי אִם appends an exception, must sometimes be supplied from the context; thus, Gn 4014 (I desire nothing else) except that thou remember me, equivalent to only do thou remember, &c. (cf. 106 n, note 2; but it is probably better to read אַךְ for כִּי). Cf. Mi 68, where כִּי אִם, equivalent to nothing but, is used before an infinitive, and Jb 428, equivalent to only, before a noun. Similarly when כִּי אִם after an oath introduces an emphatic assurance, e.g. in 2 K 520 as the Lord liveth (I can do nothing else) except I run after him, &c.; cf. 2 S 1521 Keth., Jer 5114, Ru 312 Keth., and even without the oath, Ju 157; cf. the Rem. on c.
- Very probably this use of כִּי אִם arises from the original meaning for if, surely if (כִּי in an affirmative sense); so evidently in Ex 2222 as a forcible resumption of the preceding אִם. Thus, e.g. Ju 157 is simply surely when I have been avenged of you, after that I will cease, equivalent to, I will not cease, until I have, &c. When the exception follows, an ellipse must be assumed, e.g. Ru 318 surely (or for) when he has finished it (then the man will rest). It is far less natural to assume such an ellipse with כִּי אִם but (before entire clauses as before single nouns); see a above.