1. Know that the letters used with infinitives are b-k-l-m; and it goes without saying that the vav is also used with them, for such is its usage with all verbs, nouns, and particles — except with the word o (“or”), and with the word aval (“but”), and with the word asher when its beginning is the interrogative he, as I shall explain in my book HaHarkavah in the discussion of the word ve-he’ezniḥu.

2. And know that, for the most part, the infinitive does not appear except with b-k-l-m, except when it is adjacent to a past or a future tense, such as halokh halakhta (Genesis 31:30), amor amarti (I Samuel 2:30), shamor tishmerun (Deuteronomy 11:22), abbed te’abbedun (Deuteronomy 12:2), and the like. In such cases it comes to indicate the intensification of the action, and it is usually placed before the verb, though in a few places it comes after it, such as vayevarekh barukh (Joshua 24:10), and similar cases. But when it is used with the imperative, it always comes after it, as in shim‘u shamoa‘ (Isaiah 6:9) and the like — and this is to indicate an even greater strengthening of the command.

3. Know that the letter most commonly used with the infinitive is the lamed, as in lishmor, lizkor, and the like. And even when the infinitive appears without b-k-l-m, its meaning is usually as though it were with the lamed, such as hiskalta ‘asoh (Genesis 31:28), re’oh faneikha (Genesis 48:11), which are equivalent to la‘asot, lir’ot. And every infinitive that appears in place of an imperative, such as zakhor et yom ha-shabbat (Exodus 20:8), shamor et ḥodesh ha-aviv (Deuteronomy 16:1), and the like, should be interpreted as though it were lizkor, lishmor. In that case they function exactly like true imperatives, such as zekhor, shemor. And in the other stems, aside from the qal stem, there is no difference in writing or in reading between the infinitive when it appears without b-k-l-m and the singular imperative; and this will be explained to you further in the thirteenth principle of the second treatise.

4. And as I have already said, the infinitive has no inherent tense; nevertheless, when it appears with b-k-l-m it does carry some indication of time. For with the bet and the kaf it most often indicates past time, as in binsōa‘ ha-aron (Numbers 10:35), kishmoa‘ ‘Esav (Genesis 27:34), which mean “when it traveled,” “when he heard.” And with the lamed and the mem it most often indicates future time, as in lishmor et derekh (Genesis 3:24), middabber ‘im Ya‘aqov (Genesis 31:29), which refer to the future. Thus far I have spoken concerning the infinitive; and now I shall speak concerning the imperative.

5. Know, that no prefixed particle ever comes at the beginning of the imperative, except for the vav alone. And although I have already said that the imperative applies only to the second person, I now say that one may also issue a command to the third person — but in the form of the future tense, such as ya‘aseh Par‘oh ve-yafqed peqidim (Genesis 41:34), and many similar cases.

6. And likewise, the command to the second person may appear in the language of the future, as in most positive commandments, such as tispor lakh (Leviticus 25), ta‘aseh li (ibid. 26), and the like. It also appears in the language of the past with the vav of conversion, such as ve-ahavta et Hashem (Deuteronomy 6), ve-‘anita ve-amarta (ibid. 26), and similar cases. Those that appear in the true imperative form are few, such as kabbed et avikha (Exodus 20:12), shema‘ Yisrael (Deuteronomy 6). But negative commandments never appear except in the language of the future, such as lo tirtsaḥ, lo tinaf, lo tignov (Exodus 20:13). One does not say lo retsaḥ, lo ne’af, lo gnov, because the imperative never follows any of these words: al, lo, pen, asher, et, lema‘an, ba‘avur, and the like.

7. And with regard to the speaker speaking about himself, the imperative does not apply at all, for a person does not command himself. Yet sometimes the imperative appears in the language of request and supplication, especially when directed toward the Exalted Name, as is frequently found in the Book of Psalms. And sometimes the words na or anna are added to indicate entreaty, such as selaḥ na (Amos 6), anna Hashem hoshi‘a na (Psalms 118). The imperative is also sometimes found in the language of irony or sharp exhortation, such as semaḥ baḥur be-yaldutekha (Ecclesiastes 11:9), bo’u Beit-El (Amos 4:4), and the like — though such cases are few.