Charles Ellicott Commentary John 15:8

"Herein is my Father glorified, that ye bear much fruit; and [so] shall ye be my disciples." — John 15:8 (ASV)

Herein is my Father glorified.—This clause is generally understood as referring to the words that follow, as it is interpreted in our English version. However, this rendering is open to the objection that it gives a forced meaning to the word “that” (ἵνα), which is typically used to express purpose. We may, in this case (John 16:30), take “herein” to refer to the words that have preceded. By doing so, we give a natural meaning to the words and achieve a satisfactory sense for the sentence. The thought then will be: “In this doing whatever you ask, my Father is glorified, in order that you may bear much fruit, and that you may become my disciples.”

So shall you be my disciples.—Better, and may become My disciples. The pronoun is strongly emphatic. The living union with Christ—which made all their prayers, prayers in His name, and prayers that He would answer, and made them abound with fruit to the glory of God—was the characteristic that marked them as His true disciples.