A precious fellowship with a brother enlightened my spiritual sight to see beyond the visible. It's not just a matter of being used by the Lord or even being ministers of the Lord Jesus Christ, but much more, what result does being "useful" or being "minister" ultimately yield? Is there any side-effect by such usefulness?
I was so much helped to see, that my service in the Lord should not have side-effects in any way. The Bible has a couple of examples with apostles being used yet having side-effects!
John, the Baptist was a forerunner of the Lord Jesus Christ and his ministry was to usher in the Lord, and he was useful in that aspect, truly and spiritually useful, yet his service had side-effect. Later, his follower had a problem with the Lord and His follower. Likewise, Apollos in Acts 18:25, was a brother instructed in the way of the Lord, and being fervent in spirit, he spoke and taught the things accurately concerning Jesus, but he knew only the baptism of John. Acts 19 records of his deficiency.
There are many good medicines for treatment of variety of diseases, yet many of them while being effective to the illness in turn have side-effects. Often the "side-effects" are more dangerous than the illness that was cured.
I was warned and adjusted, that I may not offer up a strange fire out of my natural zeal or talent or gifts, even spiritually, and cause side-effects to the Body of Christ. I must wait upon the Lord, and be very exercised to be fully one with the Lord and His Body in my spiritual service, wherever I serve or in whichever way I serve. May the Lord grace me not to err in my service, and that He may prohibit me in His mercy, not to take a step ahead if that would cause any side-effect.
The Lord's covering and the Lord's blessing is all that I need. "Lord grace me and keep me in you. If in Your mercy, I am counted worthy of Your use, please do so, within the limit of what You have apportioned, not beyond and not behind; and all these for Your building work."