A dove is a popular image in Christianity to depict the Holy Spirit. But note that John did not say, “I saw a dove . . .” He said “I saw the Spirit . . .” A “spirit” is not visible to the human eye. It is discernable in the human heart and mind. John was aware that the Spirit of God was in Jesus. That Spirit did not come on Jesus and then depart. It remained.
John called people to “repent” and baptized them with water as a sign they had been washed clean and could reform their lives. He knew that Jesus would baptize them, and us, with the Spirit that is in Him – the Spirit that would call and empower us to go beyond repentance and reform to seek the greatest good [the “magis”] that God desires and intends for us to achieve for ourselves and for others.
The “magis” does not necessarily mean easy and pleasant. For Jesus, in whom the “Spirit remained” it involved torture and crucifixion. For us it will at least involve challenges and difficult choices. But if we allow the Spirit to be in us, we will achieve our “magis.”