This question should never arise in the Christian church. But, unfortunately, it needs to be addressed because there are churches in America that have unbelievers leading Christians in worship on Sunday morning services. This is wrong and it is a sign of apostasy in the Christian church.
First of all, worship can be performed rightly only by believers who have been justified and sanctified by the blood of Jesus Christ (1 Pet. 2:9). Only blood-bought believers have the right to worship God because only they have a mediator by which their worship may be accepted (1 Tim. 2:5). The unbeliever has no mediator. Unbelievers do not have that right to praise God for His goodness and mercy because they are in a state of rejecting it -- which is why they are unbelievers -- and they are unclean before God! Remember how God rejected the sacrifice of Cain who was a murderer (Gen. 4:5), how much more the false and hypocritical worship of unbelievers. Jesus said to the Pharisees and Scribes, "You hypocrites, rightly did Isaiah prophesy of you, saying, 8"This people honors Me with their lips, but their heart is far away from Me," (Matt. 15:7). Are the unbelievers any better off than the Pharisees and Scribes? No, they are, like the Pharisees, under harsher judgment.
How dare the unbeliever lead the believer in worship of the true and Holy God when he or she is in a state of rebellion against God! May it never be! "But to the wicked God says, 'What right have you to tell of My statutes, and to take My covenant in your mouth?" (Psalm 50:16). Can the unbeliever praise God with the following words and not be a hypocrite? "Come, let us worship and bow down; Let us kneel before the Lord our Maker. 7For He is our God, And we are the people of His pasture, and the sheep of His hand," (Psalm 95:6). No. He cannot! To sing such praises is a mockery to God. Therefore, they are in the same state as those who are condemned by Christ on the day of judgment:
"Many will say to Me on that day, "Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?" 23"And then I will declare to them, "I never knew you; depart from Me, you who practice lawlessness," (Matt. 7:22-23).
Second, it is hypocritical for a pastor to have unbelieving musicians come into the church of the Lord and lead blood-bought believers in worship. Hypocrisy is saying (singing) one thing and doing another. It is a display of behavior of falseness. And that is exactly what the pastor is encouraging when he has unbelievers lead believers in praises to God because, in their hearts, they do not trust in the sacrifice of Christ. Their words are singing praises of trust and adoration to God when in their hearts they do not believe it. This is hypocrisy and the pastor is encouraging it.
Furthermore, I am sure that in the great majority of such hypocritical situations, the unbelievers are "praising God" for money. Think about it: a pastor offers money to unbelievers to have them come into the church of God and lead believers in worship. Worship is supposed to be an offering to God by believers and a means of preparation of the heart so that the Christian might receive the word of God in the sermon. How dare a pastor pay an unbeliever to do this!
Third, it was the Pharisees in the New Testament who had an outward manifestation of worship but inwardly were unregenerate. To this, Jesus condemned them as hypocrites (Matt. 15:7). If a pastor of a church is not informing the congregation of the the fact that unbelievers are leading believers in worship (which should never occur in the first place) then the following verses apply to the pastor:
"But woe to you Pharisees! For you pay tithe of mint and rue and every kind of garden herb, and yet disregard justice and the love of God; but these are the things you should have done without neglecting the others. 43"Woe to you Pharisees! For you love the front seats in the synagogues, and the respectful greetings in the market places. 44"Woe to you! For you are like concealed tombs, and the people who walk over them are unaware of it," (Luke 11:42).
If the congregation is unaware of the unholy and unregenerate nature of those leading them in worship, then they are inadvertently participating in the unholy worship of hypocrites. When the Pharisees worshipped God, their worship was rejected and condemned. Jesus, exposed the hypocrisy of outward worship and inward disbelief and said it "dirtied" those who followed their lead - referring to Levitical laws of cleanness. Is this not basically the same thing happening when unbelievers lead unsuspecting believers in worship? In this, the congregation thinks the worship leaders are "sanctified by Christ's blood" when, in reality they are not. And, to make it worse, the "worship leaders" further the deception on a weekly basis. Now, the pastor is the leader in the church. Woe to him who leads the church into hypocritical worship to God and encourages sinners to sin.
Fourth, we find in scripture that only believers lead worship and are involved in true worship, never unbelievers:
- "These things I remember, and I pour out my soul within me. For I used to go along with the throng and lead them in procession to the house of God, with the voice of joy and thanksgiving, a multitude keeping festival," (Psalm 42:4).
- "Ascribe to the Lord, O sons of the mighty, Ascribe to the Lord glory and strength. 2Ascribe to the Lord the glory due to His name; Worship the Lord in holy array," (Psalm 29:1).
- "But you are a chosen race, a royal priesthood, a holy nation, a people for God"s own possession, that you may proclaim the excellencies of Him who has called you out of darkness into His marvelous light," (1 Pet. 2:9).
We find no place in the scriptures where unbelievers lead believers in worship. It is not in the Bible and it should never happen in the Christian church.
What of the benefit to the unbeliever?
What about the benefit of exposing an unbeliever to the gospel by getting him into church to participate in worship? After all, it has probably led to conversions. The ends do not justify the means. If God so chooses to save someone in spite of a sinful situation, that is God's business. The pastor is to make sure that the worship honors God. It is not the place of evangelism. It is the place of worship. Do not be deceived into compromising praise and worship to God by having unbelievers participate in it.
To the pastor
If you are a pastor who has unbelievers leading believers in worship, stop it now. You are responsible for shepherding your church in truth, honor, and sanctification before God. You are responsible for the worship before the Holy Lord. This is not the realm of the unregenerate. You must repent of this sin and confess it. You must dismiss the unbelievers from worship, invite them to attend the church service, confess your sin to the elders and the church, ask forgiveness and continue in humility before men and before God.
It is far better that the worship in the church be less than perfect on the outside than have it be stained by unbelievers with unregenerate hearts.
Note: All scripture quotes are from the NASB.