"Hitherto" (King James version) is not a word that we are familiar with. It means, "to here," so in this context it implies "to this very day." Jesus is saying, "My Father is working right up to this point of time, and I am too." God is an active Creator. He did not create everything physical, and then just sit back, cross His legs, and twiddle His thumbs. He is an active Creator.
God created this universe to carry out the next step in His purpose, which is His ongoing work. He is creating a Family of beings just like Himself. He is reproducing Himself by creating us in His image. "Conversion" is the word that describes this process of transformation—"from glory to glory"—from the glory of man to the glory of God. We are being brought into the image of God.
This image is not in the way that we look, but in certain knowledge and attitudes that we believe, accept, submit to in thought and in conduct. It is accomplished by putting the mind of God in us. This regeneration begins a growth process. In our case, it is the growth of God's mind in ours.
God's mind, just like ours, is more than words. It is also attitudes, feelings, moods, passions, inclinations, and perspectives. These things can be described by words, but they are not words. They develop through the combination of knowledge and experience, most frequently within relationships. We really cannot relate to a machine, but we can relate to other beings—we can have relationships with God and men—fellowships, social intercourse, work, play, and interaction. From these experiences, these mental, emotional, and attitudinal aspects of the mind, beyond mere words, create and develop.
As it happens, nothing actually is produced that has form, weight, or can be measured. Rather it is knowledge gleaned from experience, and it is accompanied by God personally and actively working and creating to enable us to accomplish our part in carrying out His will. Remember, Paul said, "For it is God who works in you both to will and to do of His good pleasure" (Philippians 2:13).