Mussar from the weekly Torah portion

Near the end of his life, Moshe Rabbeinu commanded the people, "Now write for yourselves this song and teach it to the Israelites" (Devarim . 31:19). This verse is the source-text for the obligation of each Jew to write a Torah scroll. (According to most authorities, this mitzvah is fulfilled nowadays by purchasing books on Torah.) But why did Moshe refer to the Torah as a 'song'? In what way should we relate to the Torah as song?

Why study Mussar?

Once, a young scholar wrote Rav Avraham Yitzchak HaKohen Kook Zt"l a letter probing certain philosophical issues, raising questions that had eluded him. Rav Kook was delighted to see the scholar immerse his talents analyzing the philosophical aspects of Torah, unlike most Torah scholars who dedicate themselves solely to Talmudic and practical Halachic studies. Exploring abstract philosophical issues, Rav Kook stressed, is especially important in our times.
Nonetheless, Rav Kook urged the young scholar to approach this field only after a prerequisite study of mussar texts.

"You should first acquire expertise in all moralistic tracts that you come across, starting with the easier texts. Great scholars, wise-hearted and exceptionally pious, wrote this literature from the heart. Many subjects of inquiry cannot be fully grasped until one's emotions have been properly prepared."
In other words, it is important to precede academic inquiry into Torah philosophy with the study of simpler texts that elucidate the unique holiness of Torah. What is the function of this preparatory study? By studying mussar, we gain a proper appreciation and reverence for the subject at hand. Only after this emotional preparation are we ready to delve into an intellectual analysis of Torah.

Engaging the Emotions
It is for this reason, Rav Kook explained, the Torah is called a 'song.' Just as the beauty of song stirs our hearts, so too, the special power of mussar literature lies in its ability to awaken our inner sensitivity to the divine nature of Torah. This emotive preparation is essential, as the study of Torah philosophy only becomes clarified to those who are pure of heart.
While ethical works do not engage the intellect to a high degree, they nonetheless enable the soul to recognize its inner foundations. Of course, one should not be content reading moralistic literature, but should continue with in-depth, analytical study of the Torah and its worldview.

Hence the value of learning Mussar, and the relevance of Mussar nowadays.

This is also elucidated by the opening line of Iggeret HaRamban which quotes the verse from Mishlei:
שמע בני מוסר אביך ואל תיטוש תורת אמך

"Listen my son to the Mussar (instructions) of your father and do not abandon the Torah of your mother."

Mussar is mentioned first, implying a prerequisite to learning Torah. However the verse can also be read somewhat differently. It can be interpreted to mean :
"listen to the Mussar of your father so that you won't abandon the Torah of your mother"

By learning Mussar and gearing ourselves by familiarising ourselves with Jewish ethics, can we retain the Torah forever.