Hi brother Paul,
I believe that J.Duncan was asking this question to an unbeliever, right?
I think it cannot be applied this example in the same manner to someone who is child of God and in relationship with Christ, and the one who is not, I think it's not the same. For example, your question:
Do you think the preacher (John Duncan) was out of line in equating temporal disobedience to a temporal lack of love?
If this is unbeliever, he has no personal relationship with Christ, he has never loved Christ so that this love may stopped in given moment or to have some temporal love or temporal lack of love? The unregenerate man may have some sympathy to Christ, but not true love.
On the other side, the truly born again child of God has this love to His Saviour and Lord, to His Jesus.
1John 4:19
We love him, because he first loved us.
it's interesting that before to see your post, the very subject on which I was meditating was the love of God. I was thinking, isn't His love first that provoked us to love Him?
1Jo 4:10 Herein is love, not that we loved God, but that he loved us, and sent his Son to be the propitiation for our sins.
I started thinking, sometimes God has given me some answers comparing or thinking of some relations here on earth.
I started thinking on those questions.
I know what it means to sin against the one who you love the most. I know the brokenness and crushing thoughts that are coming after that. The very thought about that is unbearable. You can live only if you know that this sin is forgiven. You will say, why you have sinned if you loved so much? I will say, oh the foolishness of my own heart. You know that you will give the very life to the one that you love.
I don't believe that our relationships with God are mechanic and He acts like computer program. When I think about Peter and others, and when the Lord Jesus served a fish and bread to Peter, what can I say except: "For the love of Christ constraineth us;"
When our Lord Jesus said to Peter:
31 And the Lord said, Simon, Simon, behold, Satan hath desired to have you, that he may sift you as wheat:
32 But I have prayed for thee, [b]that thy faith fail not:[/b] and when thou art converted, strengthen thy brethren.
Was not the prayer of our Lord heard? I don't think so, even thought Peter said: "I know him not." after few moments.
But yes, the prayer was answered.
For me the relationship of our Lord Jesus toward Peter is something beyond my comprehension, something so high, so breaking, so...
These are my thoughts.
Thank you for listening,
Unprofitable servant,
Kire