In all learning, it is the Holy Ghost that teaches. St. Gregory the Great says: "Unless the same Spirit is in the heart of the one who learns, unprofitable is the word of the teacher. Let no one then attribute to the man who instructs him, that which he understands from the mouth of his teacher; for unless He is within Who will teach us, the tongue of the teacher labours in vain. All alike hear the voice of the speaker, yet all do not understand alike the meaning of the words they hear. Since the word is the same, why do your hearts no understand alike, if not for the reason that, although the voice of the speaker is directed towards all it is the Master within us Who teaches us what is said, and some more than others."
The Holy Ghost came to the Apostles and instructed them all, but gave His gifts in varying degrees. The same is true today. Not everyone receives the same grace and in the same manner. To some is given more and to others is given less. To those whom much has been given much is expected. It is the same Holy Ghost, but His gifts are given as He chooses. We should not despise any of His gifts. Those who have the least of His gifts actually possess great gifts. Therefore, we should love all the Brethren of the Faith, because it is the same Holy Ghost living and giving His grace to each one.
There is a kind of Divine economy in this. The varying gifts of the Holy Ghost provide us with the opportunity of sharing our talents with those who have fewer of our particular talents, and for them to share their talents with those who are lacking in these. Each one, in turn, fills up what is lacking in the others. In this manner, the Holy Ghost makes us into one complete whole. We truly become One Body in Jesus Christ — The Mystical Body of Christ. Just as the foot is not a hand, yet provides the hand with locomotion; so the hand is not a foot, but provides the labour that sustains the foot. Each complement and completes the other making one complete whole.
We must not despise those who have less than us, but rather see what the Holy Ghost has given them and bless God for the gifts He has given to the least of us. Where they may be poor in the gifts that we have been given, we are assuredly poor in the gifts they have been given. In this true appreciation, of one another, we can both give and receive from one another and make great spiritual strides in the way of perfection.
We must be cautious not to presume that what we think we know or understand is given to us by the Holy Ghost. What we do truly know is a gift from God, but our fallen nature is subject to many deceptions. Often what we think we know, we do not know. That is why God has established a living authority in the Church to maintain a correct understanding and knowledge of spiritual things. We must always be subject to those whom God has placed over us, if we are to have the Holy Ghost dwelling within us and thus truly receive the teaching that He is imparting to us through them.
The Holy Ghost was given to the Apostles twice: once by Jesus while He was here on earth, and once by the Father from on high. St. Gregory instructs us that the giving of the Holy Ghost by Jesus when He was visible in the Flesh was given for the love of one another. It is the love that we must have for each other that Jesus gave to us through the Apostles in this first giving of the Holy Ghost.
The second gift of the Holy Ghost from the Father, (that is celebrated today: Pentecost Sunday) was imparted so that we may love God, Whom we cannot see. If we do not love our neighbours whom we can see, we are incapable of loving God Whom we cannot see. It is, therefore, necessary for us to receive the Holy Ghost twice; once so that we may love one another, and then again so that we may truly love God.