When you accept an artifact, it will go to the castle of the last city you selected (viewed). In your case, that city happened to be 82|46(25). And it would appear that the hero you wanted to use it on is in a different city.
There are two ways you can go about this to solve your problem:
1) Get the hero and the Gospel of Matthew in the same city. Easiest way to accomplish this is to send the hero to the city the Gospel is in. Or you can use a hero in that city to transfer the Gospel to the city where the hero you want to use this on resides.
2) You can pay gold to transfer the Gospel to the hero you want. You do this by Castle -> Treasury -> "Transfer an artifact to a hero who is in other city" or "Transfer an artifact to another city's treasury".
Either way, once you get the Gospel and the hero in the same city, go to Castle -> Treasury, select the hero you want, and press "Transfer" on the Gospel. Then go to Leader tab in the castle, select your hero, find the Gospel, and click on Use.
Unless you are in a hurry (I don't see why) use method #1 over #2. It is a waste of gold in your case here.
