How can a phrase be both a promise and a command? It is possible, and we see a good example in scripture. God promises to fill His people with the Holy Spirit and then commands His people to be filled with the Holy Spirit.
The promise fulfilled
We first hear of God’s promise to fill His people with the Holy Spirit in John 7:37-38. When Jesus was at the Feast of Booths, He stood and cried out, “Let anyone who is thirsty come to me and drink. Whoever believes in me, as Scripture has said, rivers of living water will flow from within them.” The living water Jesus promises to fill His people with is identified in the next verse as the Holy Spirit. Jesus also promises in John 16 to send an “advocator” (or the Holy Spirit) for the people when He goes away. In Acts 1, we see a promise of receiving power to His people and that power is explained to be the Holy Spirit. The coming of the Holy Spirit to fill the lives of those who believe in Jesus was a promise made repeatedly by the most trustworthy person to ever walk on the earth, Jesus Christ.
Some of the promises of God have yet to be fulfilled, though they certainly will be in God’s perfect timing. The promise of the Holy Spirit to fill the life of believers is not one of those, however.
This is a promise that has been fulfilled.
Acts 2 describes the coming of the Holy Spirit on the day of Pentecost. This “power from on high” filled the lives of the followers who were obedient to God’s instructions to wait and receive the promise. The promise came and was fulfilled with a display of supernatural power with 3,000 conversions made from the first “spirit-filled” sermon preached by a follower of Jesus. The promise was made, and the promise was fulfilled.
The Command to obey
Now, the promise of the infilling of the Holy Spirit is also a command for believers in Jesus. In Ephesians 5:18, we are told to not be drunk with wine, but to be filled with the Holy Spirit. Both of those instructions are commands. In the same way we are commanded to not get drunk, we are also commanded to be filled with the Holy Spirit. Not only are we called to live in obedience to this command, but the verb implies continuous action. It could literally be read that we are commanded to continuously be filled with the Holy Spirit.
In Acts 2, the disciples were filled with the Holy Spirit. Acts 4:31 says they were filled with the Holy Spirit again. We too, are commanded to be filled with the Holy Spirit and to be filled again, and again, and again! Let’s be sure that we fully receive the promise, and do not neglect the command!!