Jamieson, Fausset and Brown on Hebrews 2:4

4. them--rather, "God also [as well as Christ, He 2:3] bearing witness to it," &c., joining in attestation of it."

signs and wonders--performed by Christ and His apostles. "Signs" and miracles, or other facts regarded as proofs of a divine mission; "wonders" are miracles viewed as prodigies, causing astonishment (Ac 2:22, 33); "powers" are miracles viewed as evidences of superhuman power.

divers miracles--Greek, "varied (miraculous) powers" (2Co 12:12) granted to the apostles after the ascension.

gifts, &c.--Greek, "distributions." The gift of the Holy Spirit was given to Christ without measure (Joh 3:34), but to us it is distributed in various measures and operations (Ro 12:3, 6, &c.; 1Co 12:4-11).

according to his own will--God's free and sovereign will, assigning one gift of the Spirit to one, another to another (Ac 5:32; Ep 1:5).