רַק֩ חֲזַ֨ק וֶֽאֱמַ֜ץ מְאֹ֗ד לִשְׁמֹ֤ר לַעֲשׂוֹת֙ כְּכָל־הַתּוֹרָ֗ה אֲשֶׁ֤ר צִוְּךָ֙ מֹשֶׁ֣ה עַבְדִּ֔י אַל־תָּס֥וּר מִמֶּ֖נּוּ יָמִ֣ין וּשְׂמֹ֑אול לְמַ֣עַן תַּשְׂכִּ֔יל בְּכֹ֖ל אֲשֶׁ֥ר תֵּלֵֽךְ׃
Solamente te esfuerces, y seas muy valiente, para cuidar de hacer conforme á toda la ley que mi siervo Moisés te mandó: no te apartes de ella ni á diestra ni á siniestra, para que seas prosperado en todas las cosas que emprendieres.
Mesillat Yesharim
If he leaves himself in the hands of his [natural] heaviness, it is a certainty that he will not succeed. This is what the Tana (Mishnaic sage) stated: "be brazen as a leopard, light as an eagle, swift as a deer, and mighty as a lion to do the will of your Father in Heaven" (Avot 5:20). Likewise, the Sages counted among the things which need strengthening: "Torah and good deeds" (Berachot 32b). This is explicitly stated in scripture: "be strong and very courageous [to observe and do all of the Torah...]" (Yehoshua 1:6). For great strengthening is needed for one who wants to bend his nature to its opposite.
Mesillat Yesharim
Before beginning a deed: that one not allow a Mitzva to become delayed (lit. Chametz).