Pentecost Sunday is the day churches celebrate the coming of the Holy Spirit on the Day of Pentecost as recorded in Acts 2.1-21. Luke, the disciple, mentions the coming of the Holy Spirit first in his gospel account (Lk 24.49) and I particularly appreciate the translation 'clothed with power from on high'. In these words, three ideas are given but I will focus on the aspect of power.
we look not to the things that are seen but to the things that are unseen --Paul, Apostle to the Gentiles