Jamieson, Fausset and Brown on Isaiah 11:2

2. Spirit of the Lord--Jehovah. The Spirit by which the prophets spake: for Messiah was to be a Prophet (Is 61:1; De 18:15, 18). Seven gifts of the Holy Spirit are specified, to imply that the perfection of them was to be in Him. Compare "the seven Spirits" (Re 1:4), that is, the Holy Ghost in His perfect fulness: seven being the sacred number. The prophets had only a portion out of the "fulness" in the Son of God (Joh 1:16; 3:34; Col 1:19).

rest--permanently; not merely come upon Him (Nu 11:25, 26).

wisdom--(1Co 1:30; Ep 1:17; Col 2:3).

understanding--coupled with "wisdom," being its fruit. Discernment and discrimination (Mt 22:18; Joh 2:25).

counsel ... might--the faculty of forming counsels, and that of executing them (Is 28:29). Counsellor (Is 9:6).

knowledge--of the deep things of God (Mt 11:27). The knowledge of Him gives us true knowledge (Ep 1:17).

fear of the Lord--reverential, obedient fear. The first step towards true "knowledge" (Job 28:28; Psa 111:10).