Ephesians 2:1-9 And you were dead in your trespasses and sins, 2 in which you formerly walked according to the course of this world, according to the prince of the power of the air, of the spirit that is now working in the sons of disobedience. 3 Among them we too all formerly lived in the lusts of our flesh, indulging the desires of the flesh and of the mind, and were by nature children of wrath, even as the rest. 4 But God, being rich in mercy, because of His great love with which He loved us, 5 even when we were dead in our transgressions, made us alive together with Christ (by grace you have been saved), 6 and raised us up with Him, and seated us with Him in the heavenly places, in Christ Jesus, 7 in order that in the ages to come He might show the surpassing riches of His grace in kindness toward us in Christ Jesus. 8 For by grace you have been saved through faith; and that not of yourselves, it is the gift of God; 9 not as a result of works, that no one should boast.
There needs to be nothing added, because the same mercy for every body was declared (and anyone who believes, receives it), it is sufficient and it covers all our faults - the ones that already happened and the ones that are yet to happen. It is wrong to say that some has a fullness of mercy and the other doesn't. The one who receives the mercy also believes that it is sufficient, but the one who doesn't believe it, won't receive it. If we consider this as correct - that one has the mercy and the other doesn't even if he wants to, then preaching gospel is besides point, because these whom the mercy was given to, have it anyway and the ones who weren't given the mercy wouldn't get to Heaven anyway and hearing the gospel would just grieve them. Sometimes it may look like God's word even speaks of such things, but to understand the reality of it we have to realize: 1. That there's God who has given the mercy and makes it available through His word. This is a firm and positive reality. 2. This mercy becomes a reality to salvation only after one believes, that will happen through God's word (Rom 10th chapter). Which means that if one doesn't hear the gospel, he won't be saved. He will not be saved because of a lack of mercy though. It's up to the church to preach gospel. 3. There's an enemy, who tries to hinder God's word whenever and wherever possible, but his means are not unlimited. He tries to prevent people from entering God's Kingdom and if it happens, he tries to complicate their walk with Jesus and also to prevent Christians from preaching gospel furthermore. He uses many methods and resources, but important thing to know is that his schemes are not unknown to us. His main weapon is lie and deception. Not only individual lies, but strongholds caused by ideologies, religious deceptions, that falsely assure people, who are not on their way to Heaven about their salvation... These strongholds in people's minds need to be broken down by God's word and the truth, which is the churches' commitment. Devil also uses weapons of lust (gluttony, materialism, ascetics) on Christians and by the temporal things he draws them away from salvation and eternity. 4. There's an individual freedom, or choice. When one declares that he doesn't care about God, that is not a lack-of-mercy manifestation. We have to realize that there are some, who even after hearing God's word over and over and over again, may not ever receive it.