1. Are we talking strictly about public worship or about public and private worship?
What I have in mind here is worship when we gather, worship in the assembly. Privately, what we do or don't do (provided it isn't sinful) doesn't really matter much, as I understand it. I think we get a touch as to private worship in Daniel, "he went into his house; and, his windows being open in his upper chamber toward Jerusalem, he kneeled on his knees three times a day, and prayed and gave thanks before his God, as he did aforetime." (Daniel 6:10). Of course, we can pray and worship at any time. Even in the course of a working day, we can take a moment to "let Jerusalem come into your mind." (Jeremiah 51:10). Conditions there would be different than they are in the assembly. In the assembly, all is to be done to edification. We worship together in unity, and we join with our brethren in a united note of praise. The Epistles really set out the conditions which should be in the assembly.
2. In one of the references from the New Testament, it was mentioned that one of the things they were to do involved Psalms. Do we have a historical context as to whether they would still have understood those as music or not? If I understand correctly, those were originally songs with music. (Feel free to correct if I'm wrong here.)
Psalms are experiences - a psalm describes an experience with God. Many of the Old Testament psalms were written with musical accompaniment, and "To the chief musician" (Christ, in type). As you rightly point out, psalms are mentioned in the New Testament, in Ephesians 5:19, "... speaking to yourselves in psalms and hymns and spiritual songs, singing and chanting with your heart to the Lord...", and Colossians 3:16, "Let the word of the Christ dwell in you richly, in all wisdom teaching and admonishing one another, in psalms, hymns, spiritual songs, singing with grace in your hearts to God." Every believer has their own personal psalms. Every believer has had some experience with God, some more than others. In Colossians, I think we get a wider thought than in Ephesians. In Ephesians, it is "speaking to yourselves", an inward reflection with an outward expression. In Colossians, it is "teaching and admonishing one another", edification in the assembly. Experienced brethren can bring great riches to the assembly. Their experiences can help their fellow brethren. Older brethren would normally have a great store of experience, walking with God over many years - their book of psalms is very full!
As to the historical context, there's no evidence of musical instruments being used in Christian worship until the 7th century. Contemporary sources from the time of the early church all confirm that musical instruments were never used.
3. While I would definitely commend a congregation for taking into account any known issues to their current members (the example given was to protect someone from past sin; an example I can recall from my childhood was that I had a Bible and hymn book which were larger so I could follow and properly take part in worship) I do not see how this can apply on a generalized level. If we were consciously trying to prevent every conceivable sin that every member of every congregation could have conceivable crossed paths with I would fear for our collective sanity. There's only so much that we can do without knowing what's going on.
There's certainly a danger of getting totally tied up in knots about things - letting fear and uncertainty rule our lives. In contrast to that, there's safety and certainty in staying on the ground of scripture. No scripture concerning the Church ever mentions musical instruments, so it's safe to say that they aren't necessary or even part of Christian worship. So much of the danger that's come into Christendom and into gatherings of the Lord's people - places which should be safe and supportive for all - has come about because of innovation which doesn't have a basis in scripture. We need to be on our guard against modern innovation and ancient tradition - neither of which is of God. The word of God is the only solid ground. The history of the Christian testimony is immensely instructive in that way - I would say that a good history of the Church is necessary reading for every believer. In many ways it's as sad a tale of departure and sorrow as the history of Israel - but there's an unbroken golden thread right through it. There is always the overcomer.
4. The core of worship is not what is presented, but rather how. It is the Heart of the worshiper that is of the greatest interest, and what lies within the heart is something only God can truly know.
Absolutely. If something isn't from the heart of the believer, if it's merely outward, then it has no value in the sight of God. Worship is from the heart, essentially, and only from the heart. We worship in spirit. We can't worship with our hands or our feet. Singing and speaking are both connected with Christian worship in the scripture, but I believe that that's inseparable from edification. God doesn't need us to speak or sing out loud to enjoy our worship because He is a heart-knowing God, but He commands us to do so so that others can benefit from it. The Holy Spirit prompts us and intercedes for us, so that the assembly can be edified, so that we can be built up together.
5. Perhaps the reason that we have this split thinking (or maybe it would be better to consider this a side effect of the result, since we know God would not want his children to suffer discord) is that God happens to like both a capella and instrumentally accompanied singing? He seems to enjoy a wide variety of creativity in everything else--why would music be any different?
When we're speaking about what God likes, what God takes pleasure in, what He delights in... there can only be one answer: Christ. All the craftsmanship, fine workmanship, manufacturing and building which the children of Israel did was really a foreshadowing of that One and the heavenly system of things He would introduce - which He has introduced. Faith has replaced sight, the earthly has been superseded by the heavenly.
We have a better covenant than the Jews did. "Jesus became surety of a better covenant." (Hebrews 7:22). God took pleasure in fine workmanship in connection with the tabernacle and the temple - and even lent His Spirit to it directly - because they spoke of Jesus. How patient God was during this time, because He longed, speaking carefully, to express His love fully in Christ. There came a time when the veil of the temple was rent from top to bottom (Mark 15:38), such was the eagerness (again, we would say that reverently) of God to come out to man in that way! How immensely, incomparably, incomprehensibly great was the work and Person of the Lord Jesus in the sight of the Father! If we get a sense of that, the greatness of Christ, then we come to realise how He filled up every type of the Old Testament in which God took pleasure. Then we realise that because we have Him, we don't need anything at all of the imagination, the art, the craftsmanship of man. You'll probably have seen from the length of this thread that it's been discussed a lot, and I've posted a lot on it. If it was some minor point of practice, or conformance to some rule, I wouldn't have pressed the issue. But, what we're discussing is precious truth connected with the all-sufficiency of the Lord Jesus Himself. It's not my intention to enforce some legal point on the brethren. What I deeply desire is that from this discussion we all - myself included - go forward with a deeper, fuller, greater, sweeter impression of the worth of Christ, and how, if we have Him in our hearts and present our valuation of Him to God in worship, we don't need anything else at all.
Personally? I've taken part in both types of music as worship and they both have their value. I think the more productive question that each of us could be asking is: what brings our (individual) heart closer to God? That's the goal, right?
I believe that occupation with Jesus and His love brings our hearts closer to God. If, instead, we think about how we can employ
our skills and
our talents in the worship of God, we're occupied with
ourselves. If we still think we can bring something to God as an offering which we've cultivated of ourselves, we show that we have little understanding of either the sin condition which marks man or the value of Christ. I know I've pointed to it many, many times on this thread alone, but Cain and Abel's offerings are the epitome of that, they encapsulate this truth.
Regardless, though, this is a fascinating thread. I performed both with churches and in more secular settings at various points of my life and the ways that music can be used--what it's value is--still interests me even though that aspect of my life is not a major focus at the present.
Kathy, I'm glad you've joined our discussion, these questions and remarks have been very helpful.