It may be, that someone makes a contribution in a Gathering, whether sung, spoken or prayed, that is not right.
Such things could be certain words taken from a psalm, a hymn or a song.
Some are because of a Believer's ...
being unsure of assured salvation and position in Christ,
Old Testament thinking over the New Covenant truth,
earlier adverse experiences or background,
mis-taken Old Covenant scriptures,
unbiblical church traditions over New Testament teachings,
having confused teachings from preachers, etc.
Usually the contributors are sincere. If unchecked, other Believers may take up these errors, misapplied doctrines and OT typology as truth.
Things like these call for correction. A corrected person will be grateful that there is a caring oversight to help them grow.
Let us remember that the Father is seeking those who will worship Him in spirit and in truth.
Prayer: Heavenly, Father, thank you for the wonderful ministry and work of the Holy Spirit and the power of the word of Christ.
Lord, restore this wonderful ministry of ministering to one another in psalms, hymns and spiritual songs (and the manifestation of the Spirit's gifts too!).
In Jesus' name. Amen.