What was your first experience of feeling let down or betrayed?

I remember mine well. I was aged 10, and at the swimming pool with another boy I had played with happily for years. What great fun we had that day, swimming and laughing and jumping into the pool together.

At least we did until the time we jumped in, and, through my goggles, as we rose from the bottom of the pool together, I saw my friend use both hands to make a double 'v-sign' at me and swim off. And he never spoke to me again.

Don't get me wrong – I am not losing any sleep over this now, nor do I need therapy to discuss it! But at the time I do remember I was devastated, not least because it was never clear what the reasons for his actions were. It was my first minor taste, I guess, of how cruel people can be to one another – and I am sure you have experienced the same.

As we continue our fortnightly pilgrimage through Mark's gospel we come to the place where Jesus is betrayed by Judas Iscariot, one of his 12 disciples. To make the treachery even more painful, Judas has a pre-arranged signal to let those accompanying him know who they should arrest: and that signal is a kiss. What more inappropriate symbol of disloyalty could there be?

But Jesus' betrayal was not purposeless, and it has some simple but profound lessons for all of us.

1. You will be let down. If even Christ was betrayed by one of his closest friends, how much more should we expect the same. The world is 'fallen' – out of synch with God – and it is a symptom of the fact that people reject his love that they fail to love their neighbours as themselves. Including you. Notice too that it wasn't just Judas who let Jesus down. We read (Mark 14:5) that all his disciples 'deserted him and fled'. Not one remained. So when you feel betrayed, remember that Jesus, the 'man of sorrows' has been there before you and that he feels for you in your pain.

2. You will let down others. But of course we need to remember our own fallibility also. It's easy to think of how others may treat us badly, but because we also are sinners, we likewise will let them down too. And we will also let down Jesus. In verse 51 we read how an anonymous young man is among those following Christ. When the crowd catches hold of him also during the arrest, he wriggles out of his clothing and runs off naked. Jeremy McQuoid comments: 'The unnamed naked deserter is deliberately anonymous so we can put our own names here. We are forced to examine our own willingness to abandon Jesus when the going gets tough.'

3. Christ's betrayal means you are ultimately safe. Jesus' betrayal was not some random disaster. It was part of the path that led to the cross. And the cross means that, however much fellow humans may let us down, we can be confident that ultimately, when we trust in Christ, nothing can separate us from the love of God (Romans 8:35). The Celtic spirituality writer David Adam sums it up so beautifully with this wonderful sentence: 'Underneath are the everlasting arms – and those hands have the imprint of the nails.'

4. There is a bigger plan at work. As the arrest is taking place, one of the things Jesus says is, 'Let the Scriptures be fulfilled,' (Mark 14:49). This was no accident or chance. And the same truth applies in our lives. As Bishop JC Ryle once wrote about this passage: 'Let us rest our souls on the thought that all around us is ordered and over-ruled by God's almighty wisdom. The course of this world may often be contrary to our wishes. The position of the church may often be very unlike what we desire. The wickedness of worldly people, and the inconsistencies of believers, may often afflict our souls. But there is a hand above us, moving the vast machine of this universe, and making all things work together for his glory. The Scriptures are yearly being fulfilled.'

There are some rather trite prayers about betrayal on the internet. But I prefer Psalm 55 – words written by David after treachery by someone he calls 'my equal, my companion, my familiar friend, with whom I kept pleasant company' (verses 13-14). The words are red-raw and honest – perhaps disturbingly so if we are not in his situation. And it's true that the New Testament gives us a bigger theology of how to think about this issue. But the psalm is there for a reason: that you too, when betrayed, and when the pain is most searing, may be likewise be brutally honest with God and 'cast your burden on the Lord' (Psalm 55:22). If you need to, go find and use that psalm right now.

David Baker is a former daily newspaper journalist now working as an Anglican minister in Sussex, England. Find him on Twitter @Baker_David_A The Rough Guide to Discipleship is a fortnightly series.