Hebrews 2:4

4.God also bearing them witness, etc. In addition to the fact, that the Apostles had what they preached from the Son of God, the Lord also proved his approbation of their preaching by miracles, as by a solemn subscription. Then they who do not reverently receive the Gospel recommended by such testimonies, disregard not only the word of God, but also his works.

He designates miracles, for the sake of amplifying their importance, by three names. They are called signs because they rouse men’s minds, that they may think of something higher that what appears; and wonders, because they present what is rare and unusual; and miracles, because the Lord shows in them a singular and an extraordinary evidence of his power. (33)

As to the word, bearing witness, or attesting, it points out the right use of miracles, even that they serve to establish the Gospel. For almost all the miracles done in all ages were performed as we find for this end, that they might be the seals of Gods word. The more strange then is the superstition of the Papists, who employ their own fictitious miracles for the purpose of overthrowing the truth of God.

The conjunction συν, together with, has this meaning, that we are confirmed in the faith of the Gospel by the joint testimony of God and men; for God’s miracles were testimonies concurring with the voice of men.

He adds, by the gifts or distributions of the Holy Spirit, by which also the doctrine of the Gospel was adorned, of which they were the appendages. (34) For why did God distribute the gifts of his Spirit, except in part that they might be helps in promulgating it, and in part that their might move through admiration the minds of men to obey it? Hence Paul says, that tongues were a sign to unbelievers. The words, according to his will, remind us, that the miracles mentioned could not be ascribed to any except to God alone, and that they were not wrought undesignedly, but, for the distinct purpose of sealing the truth of the Gospel.