The Spirit's fullness is not the reward of our faithfulness, but God's gift for our defeat. He was not given to the disciples in Acts 28 as the culmination and reward of their wonderful service, but in Acts 2 when they had proved themselves cowards, meeting behind closed doors.
Roy Hession (2013). “Be Filled Now: The Holy Spirit’s Role in Helping Christians Attain Spiritual Maturity”, p.8, CLC Publications