I enjoy playing the guitar and singing my own original songs, and even have recorded some, and have published them online. My question is: is there any biblical advice you know of if it is good or otherwise for a Christian to sing with instrumental music for songs that are not directly worship?
A related issue – the propriety of listening to religious music on the radio – is addressed in Answer 35, with a brief comment in Answer 88. The main difference here is propriety when not engaged in worship. What is meant by "songs that are not directly worship" is not clear. If the reference is to secular songs there is no problem, assuming that the songs are not otherwise sinful because of language used or situations addressed or described in the song. It is another issue if they are so-called "church songs." It is certainly possible to sing them without worshipping. It happens every Lord's day at the worship hour when people sing without truly lifting up their voice and praise to God and teaching and admonishing one another. Some may think it is "sacrilegious" to sing a "religious" song without worshiping, but surely that is true only when it is supposed to be and at a time that it is intended to be worship. Just as listening to religious songs is better than listening to modern music that is often "trash," playing religious music is better than playing "trash."
Two additional issues need to be considered. First, being better than something that is wrong does not necessarily make it right. Second, not all modern music is "trash" so there is a third alternative – singing good nonreligious music. While that is true, the question here is not whether there is good non-religious songs to sing, it is whether religious songs can be sung with instrumental accompaniment when it is not worship. The answer is that God has not commanded acapella singing anywhere but worship. He has commanded it in worship, and to paraphrase, "What God has enjoined, let no man put aside."
You Must Hear the Gospel
You must hear the gospel and then understand and recognize that you are lost without Jesus Christ no matter who you are and no matter what your background is. The Bible tells us that “all have sinned, and come short of the glory of God.” (Romans 3:23) Before you can be saved, you must understand that you are lost and that the only way to be saved is by obedience to the gospel of Jesus Christ. (2 Thessalonians 1:8) Jesus said, “I am the way, the truth, and the life: no man cometh unto the Father, but by me.” (John 14:6) “Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.” (Acts 4:12) "So then faith cometh by hearing, and hearing by the word of God." (Romans 10:17)
You Must Believe
You must believe and have faith in God because “without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.” (Hebrews 11:6) But neither belief alone nor faith alone is sufficient to save. (James 2:19; James 2:24; Matthew 7:21)
You Must Repent
You must repent of your sins. (Acts 3:19) But repentance alone is not enough. The so-called “Sinner’s Prayer” that you hear so much about today from denominational preachers does not appear anywhere in the Bible. Indeed, nowhere in the Bible was anyone ever told to pray the “Sinner’s Prayer” to be saved. By contrast, there are numerous examples showing that prayer alone does not save. Saul, for example, prayed following his meeting with Jesus on the road to Damascus (Acts 9:11), but Saul was still in his sins when Ananias met him three days later (Acts 22:16). Cornelius prayed to God always, and yet there was something else he needed to do to be saved (Acts 10:2, 6, 33, 48). If prayer alone did not save Saul or Cornelius, prayer alone will not save you. You must obey the gospel. (2 Thess. 1:8)
You Must Confess
You must confess that Jesus Christ is the Son of God. (Romans 10:9-10) Note that you do NOT need to make Jesus “Lord of your life.” Why? Because Jesus is already Lord of your life whether or not you have obeyed his gospel. Indeed, we obey him, not to make him Lord, but because he already is Lord. (Acts 2:36) Also, no one in the Bible was ever told to just “accept Jesus as your personal savior.” We must confess that Jesus is the Son of God, but, as with faith and repentance, confession alone does not save. (Matthew 7:21)
You Must Be Baptized
Having believed, repented, and confessed that Jesus is the Son of God, you must be baptized for the remission of your sins. (Acts 2:38) It is at this point (and not before) that your sins are forgiven. (Acts 22:16) It is impossible to proclaim the gospel of Jesus Christ without teaching the absolute necessity of baptism for salvation. (Acts 8:35-36; Romans 6:3-4; 1 Peter 3:21) Anyone who responds to the question in Acts 2:37 with an answer that contradicts Acts 2:38 is NOT proclaiming the gospel of Jesus Christ!
You Must Be Faithful Unto Death
Once you are saved, God adds you to his church and writes your name in the Book of Life. (Acts 2:47; Philippians 4:3) To continue in God’s grace, you must continue to serve God faithfully until death. Unless they remain faithful, those who are in God’s grace will fall from grace, and those whose names are in the Book of Life will have their names blotted out of that book. (Revelation 2:10; Revelation 3:5; Galatians 5:4)