The kingdom of God is like a traveller journeying along a road who takes a wrong turn. He stops on a country lane, winds his window down, and speaks to one of the local villagers:
"Is this the way to Somersham?"
"Ah, you need to turn around and..."
"Yes, but can you get to it this way?" A hand vaguely waving in the direction the car is pointing.
Well...yes...it is over that way..."
"Okay, thanks." And without thinking, off he goes.
That way, Somersham was down a network of country lanes, and would certainly involve doubling back at some point. Odds on he would need to ask someone else further on, "Is this the way to Somersham?"
Okay, so it's not one of Jesus'.
The point is, on life's journey, in order to get to where we want to be, we have to go back the way we came. If we don't do that, we are destined to drive around in circles, never quite knowing where we are, or how we get to where we would like to be. The countryside will be nice, though.
This is what Peter was getting at when he said at Acts 3:19, "Repent, therefore, and turn around..." Repentance involves regret. It wishes things had been different. It knows that we have the potential to be better - to do better.
At Philippians 3:13, Paul said, "Forgetting what is behind and straining towards what is ahead," but we cannot truly forget unless first we remember. If we fail to remember we will simply repeat the mistakes we made and continue to make decisions without any real idea of why we make them, or who we are. Jesus said a similar thing: "No one who puts their hand to the plow and looks back is fit for the kingdom of heaven."
Our whole life is affected by what was behind. We are forever influenced by it - forever looking back - we just don't realise it. It is only when we go back down the road we came along, passing every landmark and signpost - reassessing every critical event, every pivotal moment, right back to our infancy, that we can begin to change who we are into who we were meant to be. It is what Jesus meant when he told Nicodemus, "You must be born again..." or, when he exhorted his listeners, "become like this child."
We have to return to our infancy and re-interpret key events by looking at them with a mature eye. When we understand ourselves - our motives, our fears, our shame - we can forgive ourselves. This is the way our sins are forgiven. Once we have found forgiveness, "times of refreshing" will begin. Our life will change for the better.
The nation of Israel was forever being encouraged to look back. They saw their God as a God of the past as well as the present - and, when they looked back, the main thing they saw was a God who forgives. Time and again when the nation went astray, all they had to do was turn back to God and he came to their rescue. It's the main lesson learnt in the book of Judges. After the exile they didn't even need to turn back to God, he simply came and got them.
This mentality affected them right to the core. They saw themselves as God's elected, so they didn't have to do anything. This attitude bled into Christianity. No effort was required. Jesus became a super-man who waved a magic hand and people were cured. John exhorted just to "believe".
Jesus knew that more was involved if we wanted to heal our relationship with God. Hard work was required. He used expressions like the "narrow door", and "exert yourselves vigorously". It is not easy revisiting past events and engaging in self-appraisal. It can be painful and scary. Healing won't come with just a wave of the hand. Paul knew effort was required. He talked about "stripping off the old personality" and "making the mind over". Perhaps that was what he was doing when he disappeared back to Tarsus for several years. He saw that simply being a member of the nation of Israel was a futile way of being right with God. But it also wasn't enough just to switch sides. You had to go back down the road in order to get on the right track. It was the only way to 'forget the things behind'.
There were things lost in the Jesus' illustrations: a lost sheep, a lost coin, a prodigal son. And whenever they were found there was always much rejoicing.