On many past occasions and in many different ways, God spoke to our fathers through the prophets.
God formerly, etc. This beginning is for the purpose of commending the doctrine taught by Christ; for it shows that we ought not only reverently to receive it, but also to be satisfied with it alone. That we may understand this more clearly, we must observe the contrast between each of the clauses.
Here the apostle begins with a general declaration of the excellency of the gospel dispensation above that of the law, which he demonstrates from the different way and manner of God's communicating himself and his mind and will to men in the one and in the other: both these dispensations were of God, and both of them very good, but there is a great difference...
Commenting on Hebrews 1:1-3
God, who at sundry times and in divers manners,.... The apostle begins the epistle with an account of the revelation God has made of his mind and will in former times: the author of this revelation is God, not essentially, but personally considered, even God the Father, as distinguished from his Son in the next verse; for the revelation under the Old Testament is divine...