Salvation = deliverance, same word as "help", Psa_3:2.
Thy blessing is = Thy blessing hast been, and wilt be: i.e. whatever may happen to me. In this spirit he sends back the Ark (2Sa_15:25.
Selah. Connecting Psalm 3 with Psalm 4, which has the same subject. See App-66.
To the chief Musician. See App-64.
Neginoth = smitings; from nagan, to strike, as on strings. See App-65. Here the reference is to the smitings with words in Psalm3, as in Lam_3:63 (compare Job_30:9. Lam_3:14). Compare the other Neginoth Psalms: Psa_3:2; Psa_5:6; Psa_53:1; Psa_54:3; Psa_60:1, Psa_60:11, Psa_60:12; Psa_66:10-12; Psa_75:4-6 (Compare Psa_77:7, Isa_38:20, and Hab_3:19).