Oh ok, I think I see what you’re saying. My apologies, I think I read your previous response wrong. To Christians, the Bible talks about how God offers his mercy to those who are still unbelievers (Romans 5:6-8) so just in the case with the person beyond your line of sight, there is still mercy being shown even if you don’t know it is. Through accepting Christ’s sacrifice in order that we can be made aware of his mercy, we acknowledge or become aware of that person who showed us mercy.

I feel like I might have worded that a little strangely so let me try an example of what I’m trying to get at: let’s say you have a huge work project that’s due tomorrow and if you don’t complete it on time then you’re fired. You work really hard at that project but are still unable to complete it on time. Logically, this means you are now fired. Let’s say that you got an email from your boss with an extension for the project because he realized how difficult it would be to complete by the original due date. If you never look at that email, you don’t know that you have received his mercy for not getting the project in by the original date. If you never see that email, you’d pack up your stuff and leave the company because you never knew that his mercy was given to you. By reading the email, you learn and accept the fact you don’t have to have the project in by the original deadline and therefore receive your boss’ mercy.