In verses 7-11 (which appear also in 108.1-5) the psalmist promises to praise God for his saving help. My heart is steadfast expresses the psalmist’s confidence in God; the word means “firm, established.” Some (Bible de Jérusalem, New Jerusalem Bible) have “ready”; most English translations have “steadfast”; New Jerusalem Bible “firm.” In some languages My heart is steadfast, with the meaning of having confidence, is translated idiomatically as “My heart rests on God” or “I have one mind about God.”
Make melody can be better translated “I will sing a hymn (or, a psalm)”; the verb is used to refer to vocal music (see comments on “sing praise” in 7.17b).
Then the psalmist summons himself, my soul (literally “my glory”–see comment in 7.5; also 16.9; 30.12), and then his musical instruments (see 33.2) to Awake, that is, to get ready to praise God. Due to the problem of commanding oneself to awaken, it will often be necessary to shift to a parallel expression; for example, “I will awaken myself” or “I will get ready.” In some languages it is necessary to complete the expression by making explicit what one is to get ready for; for example, in the present context one may say “I will awaken myself and sing.” In languages which can not speak of waking up inanimate objects such as musical instruments, one can sometimes say, for example, “I will awaken and play my harp and lyre.” If it is not possible to maintain the poetic imagery of waking inanimate objects, the translator should look for other poetic forms that can be used meaningfully.
The next statement, I will awake the dawn, probably means that he will arise before dawn and, so to speak, wake up the sun, instead of letting the sun wake him up (see Anderson). I will awake the dawn in some languages can be said, for example, “I will wake up before dawn” or “I will get up before the sun rises.”
Quoted with permission from Bratcher, Robert G. and Reyburn, William D. A Handbook on the Book of Psalms. (UBS Helps for Translators). New York: UBS, 1991. For this and other handbooks for translators see here .