Adam Clarke on John 3:34

For God giveth not the Spirit by measure - He is the most perfect of all teachers, as having received the Holy Spirit as none before him ever did. Without measure - not for a particular time, people, purpose, etc., but for the whole compass of time, and in reference to all eternity. Former dispensations of the Holy Spirit made partial discoveries of infinite justice and mercy; but now the sum of justice, in requiring such a sacrifice, and the plenitude of mercy, in providing it, shall, by that Spirit with which he baptizes, be made manifest to all the children of men. It is worthy of remark that this was fully done after the outpouring of the Spirit on the day of pentecost, Act 2:1, etc., as may be clearly seen in all the apostolic epistles. The Jews observe, that the Holy Spirit was given only in certain measures to the prophets; some writing only one book, others two. So Rab. Acba.