I am interested in seeing how teachers on this sight would answer the following questions:
1. If someone worships God acappella, yet commits adultery, can they be forgiven?
In Romans 14 Paul speaks of practices in the marketplace: where they buy food and attend the pagan temples. Paul did not exclude people but outlawed "doubtful disputations" which would be any of the diversities practices of the sects identified by DIET but all practicing forms of wild vocal and instrumental music to drive people into a frenzy.
In Romans 15, as in other never-instrumental passages, Paul defined what he called synagogue or ekklesia which was a SCHOOL OF CHRIST.
Rom. 15:1 We then that are strong ought to bear the infirmities of the weak,
and not to please ourselves. (instrumental music and theatrics)
Rom. 15:2 Let every one of us please his neighbour for his good to edification.
Rom. 15:3 For even Christ pleased not himself; but, as it is written,
The reproaches of them that reproached thee fell on me.
Rom. 15:4 For whatsoever things were written aforetime
were written for our learning,
that we through patience and comfort of the scriptures might have hope.
Rom. 15:5 Now the God of patience and consolation grant you to be likeminded one toward another according to Christ Jesus:
Rom. 15:6 That ye may with ONE MIND and ONE MOUTH glorify God
, even the Father of our Lord Jesus Christ.
Rom. 15:7 Wherefore receive ye one another, as Christ also received us to the glory of God.
Verse 5-6 implicates "special" singing groups using their mouth to PERFORM worship for another. While they knew nothing about metrical singing (never in the Bible) their form of cantillation was a way to memorize the scheduled passage of Scripture. The Word was PREACHED by being READ.
The sole purpose was that each disciple learn a passage of Scripture so that, as history notes, they could sing it to themselves all week. That would keep evil out of their spirits and inculcate the doctrine of the systematically read text. The prophets and prophecies fulfilled was the resource Peter commended to cause the 'day star to arise in their hearts.'