חֲזַ֖ק וֶאֱמָ֑ץ כִּ֣י אַתָּ֗ה תַּנְחִיל֙ אֶת־הָעָ֣ם הַזֶּ֔ה אֶת־הָאָ֕רֶץ אֲשֶׁר־נִשְׁבַּ֥עְתִּי לַאֲבוֹתָ֖ם לָתֵ֥ת לָהֶֽם׃
Kuatkanlah dan teguhkanlah hatimu, sebab engkaulah yang akan membagikan kepada bangsa ini negeri yang telah Aku sumpahkan kepada leluhur mereka untuk Aku berikan kepada mereka sebagai milik pusaka.
Rashi
Strengthen weak hands (חַזְּקוּ) All the prophets who brought tidings of salvation consoled Israel and strengthened their weak hands. (The word) is in the intensive conjugation, and its meaning is (the causative, i.e.,) strengthen others. If he intended to say, “Be strong, you whose hands are weak,” it would be vowelized like (2 Chron. 32:7) “Be strong (חִזְקוּ) and be firm (וְאִמְצוּ).” Now that he says to them to strengthen others and to make others firm, it is vowelized, חַזְּקוּ, אַמְּצוּ. “Be strong (חִזְקוּ), do not fear” is vowelized חִזְקוּ, a form of the ‘kal’ conjugation, meaning ‘you be strong by yourselves,’ as one says to singular (Jos. 1:6), “Be strong and be firm (חֲזַק ֶמָץ),” and he does not say, חַזֵּק.