"The Holy Spirit our Efficiency Christ, in His mediatorial capacity, gives to His servants the presence of the Holy Spirit. It is the efficiency of the Spirit that enables human agencies to be representatives of the Redeemer in the work of soul saving. That we may unite with Christ in this work we should place ourselves under the molding influence of His Spirit. Through the power thus imparted we may co-operate with the Lord in the bonds of unity as laborers together with Him in the salvation of souls. To everyone who offers himself to the Lord for service, withholding nothing, is given power for the attainment of measureless results. 7T 30"
"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 Judea, and in Samaria, and unto the uttermost part of the earth."
Both passages directly link the Holy Spirit with power for service and witnessing. The EGW passage elaborates on the role of the Holy Spirit in enabling believers to be effective in soul-saving, which aligns with the promise of power in Acts 1:8.