The Scofield Bible Commentary, by Cyrus Ingerson Scofield, , at sacred-texts.com
The 40th Psalm speaks of Messiah, Jehovah's Servant, obedient unto death. The Psalm begins with the joy of Christ in resurrection (Psa 40:1); (Psa 40:2). He has been in the horrible pit of the grave, but has been brought up. Verses 3-5 (Psa 40:3-5) are His resurrection testimony, His "new song." Verses 6 and 7 (Psa 40:6-7) are retrospective. When sacrifice and offering had become abominable because of the wickedness of the people (Isa 1:10-15) then the obedient Servant came to make the pure offering; (Psa 40:7-17); (Heb 10:5-17). See Psalm 41, next in order of the Messianic Psalms.
(See Scofield) - (Psa 19:9).
(See Scofield) - (Psa 2:12).