(1) There are two divisions of Zeal. One applies before beginning a deed and the other one after beginning a deed.
(2) Before beginning a deed: that one not allow a Mitzva to become delayed (lit. Chametz).
(3) Rather when the time of its performance comes, or when it happens to present itself to him, or when the thought of performing it enters his mind, he should hurry and hasten to seize hold of it and perform it, and not allow time to go by in between. For there is no danger like its danger. Since, behold each new second that arises can bring with it a new impediment to the good deed.
(4) Our sages of blessed memory roused us to the truth of this matter in reference to the coronation of Shlomo. David told Beniyahu (in Melachim 1:33-36) "take him down to Gihon". Beniyahu replied: "Amen, may G-d say so [too]".
(5) The sages taught on this (Midrash Bereishis 76:2): "Rabbi Pinchas in the name of Rabbi Yochanan of Tzipori: was is it not already said: 'Behold, a son shall be born to you who shall be a man of tranquility. [And I will give him peace from all his enemies all around. For his name shall be Shlomo]'(Divrei Hayamim 1-22:9) ? [Answer:] Rather, because many prosecutors (mishaps) can arise from here to Gihon.
(6) Therefore, the sages of blessed memory exhorted us: "And you shall watch over the Matzot" - if a Mitzva comes to your hand, do not delay its performance (lit. allow it to become Chametz)' (Mechilta Shemot 12:17).
(7) And they said: "A person should always be quick to do a Mitzvah. For due to Lot's older daughter preceding her sister by one night she merited preceding her by four generations" (Nazir 23b).
(8) And they said: "zealous people do Mitzvot as early as possible" (Pesachim 4a). Likewise, they said: "a person should always run to perform a mitzva, even on the Sabbath".
(9) And in the Midrash (Vayikra Rabba 11:9) on the verse (Tehilim 48:15) "He shall lead us in youth" - [filled] with zeal as young maidens, as it is said: "in the midst of maidens playing the timbrels" (Tehilim 68:26) ["in youth" and "young maidens" are related words in Hebrew].
(10) For the trait of Zeal is a very high spiritual level of Shelemut (perfection) which a person's nature impedes him from attaining at the current time. But he who strengthens himself and takes hold of it as much as he can, will, in the future world, merit to truly attain it. The Creator, may His Name be blessed, will bestow it to him as a reward for his striving for it during the time of his service.
(11) The division of Zeal "after beginning a deed" is as follows. Since one took hold of a mitzva he should hasten to complete it. This is not in order to lighten on himself like one who desires to cast a burden off himself but rather out of fear lest he not merit to complete it.
(12) On this our sages exhorted us numerous times. They said: "one who begins a Mitzva but does not complete it buries his wife and sons" (Bereishis Raba 85:3).
(13) And they said: "a Mitzva is attributed only to the one who completed it" (ibid).
(14) And King Shlomo, peace be unto him, said: "Do you see a man quick in his work? He shall stand before kings; he shall not stand before lowly men" (Mishlei 22:29).
(15) The Sages of blessed memory applied this praise to Shlomo himself for hastening the construction of the Temple and not being lazy in delaying it. They likewise expounded the verse regarding Moshe, peace be unto him, for hastening in the building of the Mishkan (Tabernacle).
(16) Likewise, you will observe that all the deeds of the Tzadikim (righteous) are always performed with haste. By Avraham it is written: "And Abraham hastened into the tent to Sarah, and said, make ready quickly three measures of fine meal... And he gave it to the lad and he hastened to prepare it" (Bereishis 18:6-7)
(17) By Rivka: "and she hastened and emptied her pitcher in the trough..." (Bereishis 24:20).
(18) Likewise, they said in the Midrash (regarding the mother of Shimshon): "'and the woman made haste and ran...' (Shoftim 13:10) (Midrash:) this comes to teach that all the deeds of the righteous are done with haste". For they do not allow an interruption of time to elapse - not before beginning the Mitzva nor in completing it.
(19) You can see that a man whose soul is afire in the service of his Creator certainly will not become lazy in doing the Mitzvot. Rather, his movements will be like the quick movements of fire. For he will not rest nor be still until he has finished completing the deed.
(20) Reflect further that just like an inner fieriness of soul leads one to act with Zeal, so too the opposite, outwardly acting with Zeal leads to an inner fieriness of the soul. Namely, when one feels himself performing a Mitzva with great swiftness this will move his inner being to kindle aflame also, and the desire and want will increasingly intensify within him. But if he acts in a sluggish manner in the movement of his limbs, so too the movement of his spirit will die down and extinguish. This is something experience can testify to.
(21) You already know that what is most desired in the service of G-d, may His Name be blessed, is desire of the heart and longing of the soul. It is concerning this that King David praised his portion saying: "As a deer yearns longingly for the water brooks, so does my soul yearn longingly to You, O G-d; My soul thirsts for G-d..." (Tehilim 42:1-2), "My soul longs, and goes out for the courtyards of G-d" (Tehilim 84:2). "My soul thirsts for You; my flesh longs for You [in an arid and thirsty land (Rashi-desert), without water]"(Tehilim 63:2).
(22) But for a man in whom this longing does not burn as it should, a good advice for him is to act with zeal by force of will in order that this will bring an inner awakening of this longing in his inner nature. For the external movement rouses the inner ones and certainly the external movement is more in his power than the inner ones. Thus, if he exercises what is in his power to do, this will lead him to also attain what is not in his power. For an inner joy will awaken within him and a desire and longing through the power of acting fiery, externally, by the force of will. This is what the prophet said- "let us know, let us run to know the L-rd" (Hoshea 6:3) and "After G-d they will go, who shall roar like a lion"(Hoshea 11:10).