I have been enjoying Redemption-Accomplished and Applied. I have not read it before. Murray is not the most exciting writer on the planet. But he is precise and clear. All of these quotes come from Part II, Chapter III. Here is his definition of regeneration.
God effects a change which is radical and all-pervasive, a change which cannot be explained in terms of any combination, permutation, or accumulation of human resources, a change which is nothing less than a new creation by him who calls the things that be not as though they were, who spake and it was done, who commanded and it stood fast. This, in a word is regeneration.
And later in the same chapter
Regeneration is the beginning of all saving grace in us, and all saving grace is exercise on our part proceeds from the fountain of regeneration. (emphasis his)
And later commenting on several verses in I John (2:29, 3:9, 4:7, 5:1, 4, 18)
This simply means that all of the graces mentioned in these passages are the consequences of regeneration and not only consequences which sooner or later follow upon regeneration, but fruits which are inseparable from regeneration.
Far too frequently the conception entertained of conversion is so superficial and beggarly that it completely fails to take account of the momentous change of which conversion is the fruit. And the whole notion of what is involved in the application of redemption becomes so attentuated that it has little or no resemblance to that which the gospel teaches. Regeneration is at the basis of all change in heart and life. It is a stupendous change because it is God’s recreative act. A cheap and tawdry evangelism has tended to rob the gospel which it proclaims of that invincible power which is the glory of the gospel of sovereign grace.