But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth. Acts 1:8.
The work of the Holy Spirit is to bring power for witnessing, power for service. The promise of power, after the Holy Ghost was come, was fulfilled after the waiting time in Jerusalem following Christ's ascension. Jesus told His disciples to wait until something happened. Of course, if they weren't able to know what it was, or able to tell when it happened, they could hardly have known when to stop waiting. They might still be tarrying there in Jerusalem! So the very fact that Jesus said, "Tarry until..." indicated that they could expect something obvious to happen.
Is there something that we have not experienced in its fullness today? "The descent of the Holy Spirit upon the church is looked forward to as in the future; but it is the privilege of the church to have it now. Seek for it, pray for it, believe for it. We must have it, and Heaven is waiting to bestow it."--Evangelism, p. 701. Have you ever heard of the latter rain? Do you pray for the latter rain or do you pray for the Holy Spirit? Is there a difference? Yes, there is. The latter rain is the last outpouring of the Spirit. When you pray for the latter rain, you are praying for the end of the world, and maybe that wouldn't be a bad idea. But God gives a simple invitation to the church to pray for the Holy Spirit, which has no timetable on it as suggested by the word latter. It is something that has been present and potential and possible ever since the day of Pentecost, and even before.
If we are invited to pray for the Holy Spirit, and the invitation is to the church, then it would have to be something in addition to the converting work of the Spirit that we are asking for. When we seek power for witnessing, we are seeking something in addition, even, to power for overcoming and victory. When the Holy Spirit is given in His fullest sense, He is given to make us witnesses for Christ, to share His love with others.