them - rather, “God also [as well as Christ, Heb 2:3] bearing witness to it,” etc., 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 (Act 2:22, Act 2:33); “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, etc. - 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 (Rom 12:3, Rom 12:6, etc.; 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 (Act 5:32; Eph 1:5).