John Calvin on 2 Corinthians 9:13

13. By the experiment of that administration The term experiment here, as in a variety of other places, means proof or trial “Tesmoignage, enseignement, ou experience;” — “Proof, voucher, or trial.” For it was a sufficient token for bringing the love of the Corinthians to the test, — that they were so liberal to brethren that were at a great distance from them. Paul, however, extends it farther — to their concurrent obedience in the gospel. “Leur obeissance qu’ils rendoyent tons d’vn accord a l’euangile;” — “Their obedience which they rendered, all with one accord, to the gospel.” For by such proofs we truly manifest, that we are obedient to the doctrine of the gospel. Now their concurrence appears from this — that alms are conferred with the common consent of all.