The Holy Spirit would have many functions, the most important of which was to endue them with power to spread the Gospel: But ye shall receive power after that the Holy Ghost is come upon you; and ye shall be witnesses unto me...to the uttermost part of the earth. (Acts 1:8) Following Jesus's instructions, the believers waited in Jerusalem for the Holy Spirit.
Ang Espiritu Santo ay may maraming gawain, ang pinakamahalaga ay upang bigyan sila ng kapangyarihan na ikalat ang Ebanghelyo: Datapuwat tatanggapin ninyo ang kapangyarihan, pag dating sa inyo ng Espiritu Santo: at kayo y magiging mga saksi Ko hanggang sa kahulihulihang hangganan ng lupa. (Gawa 1: 8)