Rashi: My heart moves within me in your praise of Chachamim. Every expression of Shirutz and Richush refers to movement. Radak - this is like Rechushei Merachashin Sifvasei (Sanhedrin 90b); he moves his lips, but his voice is not heard. This word is proper for 'speech' of the heart; it is not heard until his lips say it. The heart is the source of words, just like the source of a spring is the source of water.

Malbim: Three matters determine the quality of a song. (a) The words of intellect and Chachmah in it. "Rachash Libi Davar Tov" teaches that under the external cover of the metaphor of the song, there is living, moving Chachmah. The other matters are (b) the subject, and (c) the metaphors and expressions. Refer to 45:2:2:3, 45:2:3:3.

Malbim (Derech ha'Muskal): The revealed part of the song is Chulin, about love of a foreign woman. In my heart there is a dear treasure [embedded in the song].

Rashi: I established this song to say it to (a Chacham, who is proper to be) the king - "Bi Melachim Yimlochu" (Mishlei 8:15).

Radak: My deeds, i.e. this song that I compose, are for Melech [ha'Mashi'ach].

Malbim: This song is for the honor of the king.

Malbim (Derech ha'Muskal): The revealed part of the song discusses a king [marrying a woman].

Rashi: My tongue is clear in songs like the pen of a skilled scribe. R. Moshe ha'Darshan says that in Arabic, Mahir is expert.

Radak: My tongue speaks quickly about [Melech ha'Mashi'ach], like the pen of a swift scribe writes without delay.

Malbim: Just like an adept stenographer writes all words of the speaker and does not miss a word, so my tongue, which is the scribe's pen of the heart, will record every thought of my heart.

Malbim (Derech ha'Muskal): The revealed part of the song is the pen of a skilled scribe, who clothes Chachmah in a parable, and only a Chacham sees the Chachmah.