It is taught in the Tikunei Zohar that the actual sound of melodies contains an allusion to the letters of the Name of G‑d [Havayah]:
There are then types of 'wheels', or 'breaths', stemming from the mouth. They are known as 'wheels' because they roll as they ascent from sefira to sefira, and they include all ten sefirot. They add up to ten, hinting to yud, the first letter of the Name, whose numerical value is ten, and which corresponds to the ten fingers; that is, they represent the function of tiferet of mitigating gevura. The five fingers of the left hand, as well as the five fingers of the right hand pluck the stings of the harp to draw out the melody. These ten fingers elevate the breath expressing the sound of the melody, and they are composed of five and five, corresponding to the first and last letter hei [= 5] of the Name. They ascend and descend through the six intermediate sefirot [chesed, gevura, tiferet, netzach, hod, yesod], which correspond to the vav [= 6] of the Name. The sounds therefore contain the complete Name, and they are like a ladder of six steps by which the breaths ascend and descend. (Tikunei Zohar 27b)
One of the ways which lead to meditative attachment is to sit in seclusion for a certain length of time every day….
One of the ways which lead to meditative attachment [in Hebrew, "deveikut"] is to sit in seclusion for a certain length of time every day and dwell on the greatness of the Creator, as we have explained …. One should then read Job's final answers to the Most High: "Job then responded to G‑d, and said, 'I knew that You can do everything, and that nothing can impede [Your] purpose from You. Who is it that would deny [Your] counsel without knowledge? Therefore I declared, yet I understand nothing. It is beyond me. I have heard of You through hearsay, but now my eye had beheld You! Therefore, I renounce [my words] and relent, for [I am but] dust and ashes.'" (Job 42:1-6) Say these verses slowly and out loud, in an attempt to understand their meaning.
On a similar note, Rabbenu Tam (in Sefer Hayashar, Gate 13) suggests that once a week one should make a practice of reading G‑d's answer to Job out of the whirlwind, "Gird your loins like a warrior!" (Job 39:1-3) Rabbeinu Yonah (end of Gate of Awe) tells us to read every day the verse "Now, O Israel, what does G‑d, your G‑d, ask of you? Only that you fear
G‑d…" (Deut. 10:12) It is good to follow their advice.
Furthermore, during the morning prayers, read the psalms of praise out loud, paying attention to the meaning of the words, and you will attain deveikut. You should also make it a daily practice to read a few chapters from the Book of Psalms in the synagogue, in a loud voice and with direct intention. It would also be beneficial to read the psalms with kabbalistic meditations, as Kabbala teaches, through some of the divine names mentioned in the Zohar.
The Torah is also referred to as "song"….
In the same way that the sound of a song leads to deveikut, the Torah is also referred to as "song"; similarly, it also causes deveikut. As the Sages expounded on the verse "Even by night his song is with me", (Psalms 42:9) the song of the Torah only emerges during the night.
Rabbi Daniel Frish explains that the song and praise of the Torah does not refer to actual songs or recital of psalms, but rather to Torah study, whether Talmud, Jewish law, or the like. (Matok MiDevash vol. 5, p.504)
The main goal of these songs, whether the Torah song or other type of song, is to provide a source of arousal for the Shechinah, as the verse says, "So that my soul might sing to You and not be stilled; G‑d, my L-rd, forever will I thank You." (Psalms 30:13)
David's Torah study was part of his songs of praise….
Yet, David's exclamation that he would thank G‑d forever, so that his soul might sing should not be interpreted literally, namely that he limited himself to the composition of song - for if so, when did he study the Torah? It is clear that David's Torah study was part of his songs of praise and gratitude, as expressed in the verse "I will give thanks to You with an upright heart, when I study Your just laws." (Psalms 119:7)
One of the ways in which you are required to show your love for the King is to honor Him and sing before Him in the synagogue, just as one sings in front of a king of flesh and blood in order to honor him. Praising the King is equivalent to honoring Him, as the verse says, "While in His Sanctuary everyone declares 'Glory!'" (Psalms 29:9)
[Translated by Simcha Benyosef]