Haydon spoke on Acts 1:4-9 on three 'buts' in the passage. 1. '..but wait for the promised Holy Spirit'. This was still a dynamic situation of change and there was more to be received. This remains true for us - there is always more. 2.'..but you will be baptised'. Jesus compares and contrasts regarding Johns baptism and the promised baptism of the HS.
3. '..but you shall receive power when the HS comes upon you'. Jesus responds to our questions, which is how genuine relationship grows.