Who is Qualified to Serve
Reflecting on that question, based on the Bible and my own experience serving the Lord Jesus full-time, I can only tell her, "It's true but that fact may also be misused by the enemy."
No one is qualified to serve the Lord because there is only one Person who can be well-pleasing to the Father, that is the Son Himself. However to this day, many have served the Lord and ministered to Him because "grace and reality came through Jesus Christ."
In other words, Christ Himself has become the grace to be enjoyed and experienced by us as well as all the reality of who the Triune God is and can be to us. Christ has become the secret to empower us to do all things in Him. Of course, the "all things" here pertains to everything that is aligned to the Father's perfect will.
The enemy uses the fact that we are not qualified to serve so that we would give up on finding grace, give up on subjectively experiencing Christ as everything to us in our life and service. We have to realize that when we give up on finding Christ as grace, we will only be left with our own condition. When we give up on experiencing the practical Christ daily, we will be stuck in our pitiful state.
The way to experience Christ daily is by turning to our spirit who has been joined to the Spirit (1 Corinthians 6:17). One simple way to turn is by calling on His name, "O Lord Jesus, how I need You today. Cause me to love You more."
1 Corinthians 15:10 says,
"But by the grace of God I am what I am, and His grace toward me did not prove vain; but I labored even more than all of them, yet not I, but the grace of God with me."