How is Lispor the opposite of Likro'a?
Rav Sadya Gaon: Likro'a is to scatter; Lispor is to unite.
Rashi: Likro'a is tearing away [10 tribes from] Malchus Beis David - "va'Ekra Es ha'Mamlachah" (Melachim I, 14:8); Lispor is "v'Hayu la'Achadim b'Yadecha", "v'Lo Yechatzu Od li'Shtei Mamlachos" (Yechezkel 37:17, 22).
Metzudas David: He tears a garment or curtain, and sews what he tore.
What is the significance of a time to be quiet and a time to speak?
Rashi (based on Zevachim 115b 1 ): Sometimes one is rewarded for silence 2 - "va'Yidom Aharon" (Vayikra 10:3). He merited that the next Dibur was said to him 3 - "va'Ydaber Hashem El Aharon? Yayin v'Shechar Al Tesht" (ibid. 8-9). Sometimes one is rewarded for speaking - "Az Yashir Moshe" (Shemos 15:1), "va'Tashar Devorah" (Shoftim 5:1), "Kechu Imachem Devarim" (Hoshe'a 14:3).
Rashbam: Only these [and "Es Laledes" (2)] do not depend on "Es Milchamah v'Es Shalom."
Metzudas David: He does not answer one who reviles him. He answers one who reviles him, when he desires.
Torah Temimah citing 115b: "Dom la'Shem v'Hischolel Lo" (Tehilim 37:7) - even if Hashem makes Chalalim for you (your close ones die), be silent.
Metzudas Tziyon: "Lachashos" is silence, like "va'Yecheshu Galeihem" (Tehilim 107:29). Ibn Ezra - it is like "Hecheshu" (Melachim II, 2:3). That is past tense, like He'elu Afar Al Rosham" (Eichah 2:10). If it were a command, there would be a Patach under the Hei. Shlomo's Chidush is that there is a time even for speech.
Refer to Vayikra 10:8:151:1-2 and the notes there, refer to Vayikra 10:8: