The book of Acts has previously been described as "The Holy Spirit of God - working through the Word of God - in the hearts of the People of God." That's an appropriate description of the goings-on here in Acts as the post-crucifixion Christian Church was just being established. Many Bible scholars have also turned to Acts one, verse eight as the key statement of the facts --- in Acts - the Holy Spirit descended upon the believers on the day of Pentecost.