"Dr. Fletcher Wharton, in a published sermon, asks, 'What is it, then, to have this spiritual power?' He answers: 'Let me answer. Let me answer slowly. It is to have God in our souls. Not some other one's experience of God, but God. Ye shall receive power after that the Holy Ghost is come upon you.
"President Finney says that the term 'power,' used in our text, means 'The power to prevail with God and man, the power to fasten saving impressions upon the minds of men.'
"Dr. Adam Clarke says: 'The apostles were endued with power for three purposes, one of which was that their preaching might be attended by the power of the it, so that their hearers might believe and be saved.'
"Says Dr. B. M. Long: 'Our efforts will be futile unless we are anointed by the Spirit of God.' He adds this important truth: 'Too many of us are satisfied with conversion, and therefore fail to go forward and get the anointing of the Spirit, the baptism of power.'
"Mrs. Booth: 'I most unhesitatingly assert that the great want is power.'
"Mr. Moody: 'God has a great many sons and daughters without power. A great many people are thinking that we need new measures. That is not what the Church of God needs today. It is the power that the apostles had. When the Spirit of God is upon us for service, we are anointed, and then we can do great things. So we are not going to lose anything if we tarry till we get this power.'
"Mr. Finney said: 'No one has at any time any right to expect success unless he first secure this enduement of power from on high. It is the supreme need of today.'
"F. B. Meyer: 'His human nature needed to be empowered by the Holy Spirit before even He could do successful service. If Christ waited to be anointed before He went to preach, no young man ought to preach until he, too, has been anointed by the Holy Ghost.'
"Mr. Moody: 'Even Christ Himself did not undertake the great work of preaching until the Holy Ghost descended upon him for this special service.'
Taken from 'It Brings Power' by Aaron Hills http://articles.ochristian.com/article6799.shtml