Matthew 28:19 also shows us that when we go to disciple others, we need to have the realization that we are in the Triune God. We not only have the authority of Jesus but also are one with Jesus. We are in the Triune God. We are not going to teach others some religion. We are going to baptize them into the Triune God.
According to the grammatical construction of Matthew 28:19, to disciple the nations is by baptizing them. You have to baptize them into something. To baptize is to dip. If I baptize my eyeglasses, this means I dip them into something else. Likewise, if I am going to baptize someone, this means I am going to put him into something else. When we baptize others, we put them into the Triune God. To disciple the nations is to baptize them into God, to put them into God.
If you are going to put others into God, you surely need to be in God first. Then you can tell others that you are in the Triune God and that you want to put them into the Triune God. You could say, "I have no intention to put you into Christianity. I have no intention to put you into any denomination, any sect, or any group. My intention is to put you into the Triune God, in whom I am. I am in the Triune God, and I am going to put you into the Triune God, in whom I am." This is different from the preaching of the gospel in a low way. You need to have the realization and the assurance that you are putting people into God, because you are in God.
We need power to preach the high gospel. In Luke 24:49 the Lord told the disciples to "stay in the city until you put on power from on high." And in Acts 1:8 He said, "You shall receive power when the Holy Spirit comes upon you." When the power from on high comes upon us, we will be qualified and equipped for witnessing unto the uttermost part of the earth. If you mean business with the Lord, and if today you are high on the top of a mountain, realizing that all authority is His and that you are really in the Triune God, then you already have the power. You just need to claim it. When you go to the young people, you have to tell the universe, "I have the power!" You should have this kind of faith. Do not care for your feeling or for your experiences. You have to care for the Word of God. When you go to disciple the unbelievers, you need to have the faith that you are in the power.
(The Life for the Preaching of the High Gospel, Chapter 7, by Witness Lee)