Ten days after his glorious Ascension into Heaven, the Lord fulfilled his promise to send the Holy Spirit to his disciples. The day this happened was no coincidence. That day was the solemn feast of Pentecost, which the Jews had celebrated for centuries. Pentecost was a feast of thanksgiving to God for the first fruits of the wheat harvest. Pentecost also celebrated the commemoration of the Law given to Moses in the desert.

These two reasons for the feast took on new meaning the day the Holy Spirit descended upon the disciples. It is no longer a harvest in agricultural terms but in spiritual terms: it is the first fruits of the harvest of the Holy Spirit given to the Church. It is no longer solely focused on the old law given to Moses, but also includes a new law given by the Lord, summed up in the commandment of love. The Holy Spirit brings this new Law of God and instills it into the hearts of the disciples.

The Lord says to his disciples, "I will pray to the Father, and he will give you another Advocate to be with you always, the Spirit of truth." The Holy Spirit is a gift from the Father. The Lord himself asked his Father for this gift.

The Lord refers to the Holy Spirit as a Paraclete, which means an advocate, an intercessor. The Paraclete is the one who helps us, protects us, and is at our side in our journey and in our struggles against evil. The Lord speaks of the Holy Spirit as another Paraclete. The reason is that the Lord was the disciples' Paraclete while he was with them in this world. Now that he was returning to the Father, the Lord would not abandon his disciples but would send them another advocate.

The Lord also says, “The Advocate, the Holy Spirit, whom my Father will send to you in my name, will teach you all things and will remind you of everything I have said to you.” The Lord speaks of two essential functions of the Holy Spirit: to be the teacher who instructs the disciples on the Lord’s doctrine, and to be the memory that helps them remember what they have been taught.

The Holy Spirit does not bring a different teaching but rather makes the Lord’s teaching present throughout time without losing its authenticity. The Lord’s disciples can imagine themselves as plants that the Holy Spirit, like a gardener, grafts. The Holy Spirit grafts or instills the Word of the Lord into our hearts. This gardener helps us make this teaching a part of us like a new plant. Part of the Holy Spirit's work is to prepare our heart to truly receive the Word of the Lord. Pope Francis taught that "every time the Word of Jesus is received with joy in our hearts, this is the work of the Holy Spirit."

The books of the New Testament are a production of the Holy Spirit. St. Peter wrote, “No prophecy ever came through human will; but rather human beings moved by the Holy Spirit spoke under the influence of God” (2 Peter 1:21). We, as the Lord’s disciples, also need to help the Holy Spirit do his work in us. Here we understand the importance of personal and communal prayer. It is in prayer that the Holy Spirit prepares our hearts to receive the Lord's teaching. Every time we pray, we must have the Word of the Lord with us.

On this important solemnity, let us humbly ask the Lord to grant us grace to receive his Word and put it into practice by the power of the Holy Spirit.