Fervent in Spirit

Love must be without hypocrisy. Detest evil; cling to what is good. Show family affection to one another with brotherly love. Outdo one another in showing honor. Do not lack diligence; be fervent in spirit; serve the Lord. Rejoice in hope; be patient in affliction; be persistent in prayer. Share with the saints in their needs; pursue hospitality. Bless those who persecute you; bless and do not curse. Rejoice with those who rejoice; weep with those who weep. Be in agreement with one another. Do not be proud; instead, associate with the humble. Do not be wise in your own estimation. Do not repay anyone evil for evil. Try to do what is honorable in everyone’s eyes. If possible, on your part, live at peace with everyone. Friends, do not avenge yourselves; instead, leave room for His wrath. For it is written: Vengeance belongs to Me; I will repay, says the Lord. But
If your enemy is hungry, feed him.
If he is thirsty, give him something to drink.
For in so doing you will be heaping fiery coals on his head.
Do not be conquered by evil, but conquer evil with good.
(Romans 12:9-21 HCSB ©®)

A Jew named Apollos, a native Alexandrian, an eloquent man who was powerful in the Scriptures, arrived in Ephesus. This man had been instructed in the way of the Lord; and being fervent in spirit, he spoke and taught the things about Jesus accurately, although he knew only John’s baptism. He began to speak boldly in the synagogue. After Priscilla and Aquila heard him, they took him home and explained the way of God to him more accurately. When he wanted to cross over to Achaia, the brothers wrote to the disciples urging them to welcome him. After he arrived, he greatly helped those who had believed through grace. For he vigorously refuted the Jews in public, demonstrating through the Scriptures that Jesus is the Messiah.
(Acts 18:24-28 HCSB ©®)

What is the opposite of “fervent in spirit?”
We need to be unswervingly devoted to not be whatever that is.