Jack Cottrell is an Arminian theologian. If you want to read a serious Arminian, start with him.
Cottrell wrote a summary of his beliefs—a short systematic theology—called His Truth: Scriptural Truths About Basic Doctrines. The last chapter is on assurance.
At the beginning of the chapter, he identified two prominent errors regarding assurance.
The first was the doctrine of “once saved, always saved,” by which he meant the Calvinistic doctrine of the perseverance of the elect. Cottrell got that subject very wrong (see here).
The second was to deny that assurance is possible.
He called it the “trying hard, never sure” position. Cottrell affirms that assurance is possible. But how?
You could call his view the “I hope I keep believing” position.
Cottrell knows that assurance is based on faith in Christ for salvation, not on works:
“our assurance of salvation is not conditioned upon works. As we have already seen, we are justified by faith apart from works measured by law (Rom 3:28). Knowing that we are justified by faith is the real key to assurance…To put it another way, our sense of assurance derives from knowing we are justified by the blood of Christ, not from our having achieved a certain level of sanctification” (His Truth, 115).
That is mostly right.
Genuine assurance is tied to believing in God’s promise of eternal life (or the equivalent concept, such as justification).
Cottrell almost got it right here.
But he made a fatal error. What is it? He changed the condition of justification.
When Paul explained how you are justified, he used Abraham as his example (Rom 4:1-2). The patriarch was justified when he believed God’s promise. He was reckoned righteous that very night, in a moment of faith. Not the next day, or the next month, or the next year. He was justified that night.
Likewise, you, too, are justified in a moment of faith. Whenever you believed in Jesus for eternal life, that is when you received it.
Justification does not require two minutes of faith, or two hours, or two years, or two decades, let alone a lifetime of continuous believing. It takes a split-second (see here and here).
But not according to Cottrell.
He thinks salvation depends on a lifetime of faith:
“To be justified by faith means that this peace and freedom are not conditioned on how good we are (i.e., works), but on our continuing trust in the all-sufficient blood of Christ” (In Him, 115, emphasis added).
For Cottrell justification is provisional, not permanent, and the condition of justification is a lifetime of faith, not a moment of faith. Consequently, he thinks you can lose your justification salvation if you stop believing:
“As long as we freely continue to trust God’s gracious promises, He will keep us in His grace. If we cease to trust, then by our own decision we cut ourselves off from Him” (His Truth, 114).
But if salvation depends on persevering in faith until the end of your life, doesn’t that create uncertainty? Cottrell recognizes you can never be sure that you’ll persevere:
“As long as we have sincere faith in God’s promises in Jesus Christ, we can be sure of our present relationship with God. But there is always the possibility that sometime in the future we may lose our faith and fall from grace (Gal 5:4). We assume, though, that every sincere Christian will do his very best to maintain his trust in Jesus Christ” (His Truth, 114-115).
Since you can’t know if you’ll persevere in faith until the end of your life, you can’t be sure of your salvation. You can hope. You can wish. You can think it’s probable. But you can’t have assurance. There will always be a doubt, a question, an element of uncertainty.
So, if Cottrell’s answer is not a real solution, how can you have assurance?
It’s simple. Believe Jesus’ promise of eternal life.
For example, you can think of assurance as a syllogism (see here and here).
Premise 1: Whoever believes in Jesus has everlasting life (John 6:47).
Premise 2: I believe in Jesus.
Conclusion: Therefore, I have everlasting life.
If you believe that conclusion—i.e., “I have everlasting life”—you have genuine assurance. You believe you “have” everlasting life as a present possession. And since it is everlasting, you believe you cannot lose it. If you believe you can lose it, you have not yet believed in Jesus for what He promised (see here). Go back to the first premise, read it over until you believe it.
Cottrell hopes he will keep believing. I hope he will start believing.