1 You know well, Beloved, that we all have One Master, and are fellow disciples under Him. Nor are we your masters, because we speak to you from this higher spot; but He is the Master of all, who dwells in us all. He just now spoke to us all in the Gospel, and said to us, what I also am saying to you; but He says it of us, as well of us as of you. “If you shall continue in My word,” not of course in my word who am now speaking to you; but in His who spoke just now out of the Gospel.
“If you shall continue in My word,” says He, “you are My disciples indeed.” To be a disciple, it is not enough to come, but to continue. He does not therefore say, “If you shall hear My word;” or, “If you shall come to My word;” or, “If you shall praise My word;” but observe what He said, “If you shall continue in My word, you are My disciples indeed, and you shall know the truth, and the truth shall free you.” What shall we say, Brethren? To continue in the word of God, is it toilsome, or is it not?
If it be toilsome, look at the great reward; if it be not toilsome, you receive the reward for nought. Continue we then in Him who continues in us. We, if we continue not in Him, fall; but He if He continue not in us, has not on that account lost an habitation. For He skills to continue in Himself, who never leaves Himself. But for man, God forbid that he should continue in himself who has lost himself. So then we continue in Him through indigence; He continues in us through mercy.
Source: Sermons on Selected Lessons of the New Testament (New Advent)