The disciples are more than aware of the fact that they are going to need help in the days to come. While they are not entirely sure of what will face them – they know they will face insurmountable situations in which they need supernatural strength. Remember, we were not given a spirit of timidity …
And this is exactly what Jesus promises them. He says they “you will receive power when the Holy Spirit comes” to them. This is not just a promise for them, but for all of us. For throughout the book of Acts we see the Holy Spirit does bring power for the people of God to do what God has called us to. Which means, that we really have all the power we need – rather than ask God for it then, we need to ask him to wake us up to the fact that it is already here.