To the extent that a person has assurance of salvation, where is that assurance found?
This question is aimed at finding out where someone looks for the assurance of their salvation. If someone asks you, for example, whether or not you are "saved" and you say "Yes", then on what basis do you say "Yes?" Do you look at your lifestyle, your behavior, your good works, and conclude: "Well, I must be saved because… look at my performance. Look at all these things that I'm doing for God. Look at how obedient I am." Or, do you say "Yes, I'm saved because Christ promised me that I'm saved if I place my trust in Him and I have done so and I believe the promises of God and therefore I know I'm saved."
Those are two very different perspectives. When I put this question to the four groups, I get essentially two answers, though the LDS answer added another twist:
Latter Day Saints (Mormon):
Of course we know now that the LDS has, well, limited assurance to begin with. But whatever assurance they do have, according to the LDS missionaries I met with, comes from their subjective feelings, (the 'burning in the bosom) the so-called “modern prophets,” scripture, (which includes their other books) but most of all their works and obedience.
The Watchtower (Jehovah's Witnesses):
In Watchtower doctrine, you provide your own assurance which is based on your own performance. Your own actions determine your eternal destiny. Your sense of whether or not you will ultimately be resurrected (as opposed to annihilated) comes from your performance. Are you spending enough time going door-to-door, are you obedient, etc.
Whatever assurance a Christian might have -- according to many popular teachers -- comes from examining themselves to see if they are in the faith; assessing their own walk and perhaps even by noting whether they are worried about whether or not they’re saved. Assurance comes from what you do, in other words.
If there’s no evidence of salvation in your life now, you need to face the fact that you may not be a Christian -John MacArthur
Here, MacArthur is directing the reader to look to their own performance for assurance of salvation. If it isn't evident (evident to whom, one might ask) that you're a Christian, then you might not be.
People who don't keep their promises to God don't really know the Lord -James MacDonald
MacDonald is doing the same thing as MacArthur… look at your performance. If you don't keep your promises to God, then you're not saved. You see, that's a performance issue. Conversely, if you are keeping your promises to God, then you are saved. Look to your performance, MacDonald is saying.
…The question hit me, ‘R.C., what if you’re not one of the redeemed? What if your destiny is not Heaven after all but Hell?’…I thought ‘Well, it’s a good sign that I’m worried about this because only true Christians really care about salvation. -R.C. Sproul
Here Sproul finds some assurance in the fact that he's concerned about whether or not he is going to Heaven. Only a true Christian would care about such a thing, after all. But this assurance is coming from something he does… namely, caring about salvation.
The bottom line is that these Lordship teachers find their assurance in exactly the same place as Mormons and Jehovah's Witnesses: They look at their personal performance. Here's a quote from John Piper to demonstrate this:
How does [Isaac] maintain and warrant and have assurance that he is right with God and that he will be right with God at the end of the age? And the answer that James gives is he'll be justified in that sense, he will continually be regarded as just by the works which show that he passes the test for the authentication of his faith. -John Piper
In this quote, Piper asks how someone can have assurance of their salvation. And clearly, John Piper believes the answer lies in the person's works. The person should look for assurance in their own personal performance in the Christian life.
Now if we're looking at our personal performance to assess whether we're saved or not, upon whom does our salvation depend? On God? Or on ourselves? Looking at my own performance for assurance demonstrates that I'm not trusting in Christ's promises, but I'm trusting in my works instead.
Once again, the Free Grace perspective provides an answer that is totally and absolutely distinct from the other three groups. 100% assurance comes from the promises of God and the work of Christ on the cross. If you believe the promises of God, you are saved. Period. God said it, Christ did it, I believe it, that settles it. Assurance is not located in my own performance in any way because my salvation does not depend on me and my performance. It depends on God.