8 I speak not by commandment, but I am testing the sincerity of your love by the diligence of others.
In verses 8-15, Paul shows how Christ’s self-imposed poverty by the incarnation motivates the church to give sacrificially.
8 I speak not by [according to the standard of] commandment,
Paul does not command the Corinthian church to give because that would violate the principle of grace. They would not give freely. It would be a matter of compulsion. The apostle does not operate according to the standard of “commandment” but according to the standard of grace.
Nowhere in chapters 8 and 9 is there a command to tithe. Tithing is absent from any challenge to the church.
but [strong contrast] I am testing the sincerity [genuineness] of your love
Paul tested the genuineness of the Corinthian church’s love for Christ. The Greek word for “testing” means to test for the purpose of approving. Paul tested the Corinthians to approve of their way of giving to the Lord. The true test of love is not emotional but action toward God and others (1 Jn 4:20-21). That is how Paul gauges one’s love for others. We can see legitimate love for Christ in how we give to others.
“Sincerity” means genuineness. Paul wanted to know the reality of Corinthian giving; he tried to determine whether they were giving from proper motives.
by the diligence of others.
The “diligence of others” here is the way that the Macedonian churches to the north of Grace gave to the cause of Christ (2 Co 8:2). “Diligence” always pertains to how people apply what they know. They were the standard by which the genuineness of the Corinthians gave.
The fundamental principle of giving in the church is freewill, an extension of the state of the soul.
Christian giving invites or encourages people to contribute to the Lord. This invitation is motivated by God’s love and provision for the believer. Christians must give for the right reason, that is, their love for the Lord and His people. Love will demonstrate itself by one’s giving pattern. This is what we call grace-giving.
What is not free and willing is not generous. Those coerced into giving do not truly contribute to the Lord. The actual test of biblical giving is how the attitude reacts to give. One’s proper perspective will show itself in giving to Christ. Any man can tell a woman that he loves her; the question is whether he means it. Genuine love will demonstrate it with action.
Grace-giving does not necessarily imply that we give less than Old Testament believers, but the idea is that we do not contribute to keep the law but to prove our love for God. We provide, not out of compulsion, but because what God did for us impels us to do so.