Gal 4:8-11

Paul writes more than once about how entering a Christian life is turning from false gods to the one true God - see 1 Thess 1:9-10.
In this short paragraph Paul writes of the on going temptation faced by Christians to make the return trip. It might be that this is the key theme of Galatians - 1:6, 10; 2:5, 13, 14, 18; 3:3, 4; 5:1, 2, 4, 7, 8. Having become Christian by the work of God through his Spirit we are often tempted to regress to a form of self-help religion which denies the gospel.
It is possible that Paul's writing on justification and righteousness in chapter 3 is done in service of calling Christian back from this error of abandoning the gospel.
4:9 - Paul is asking how can we do this.

We are attracted by ceremonies, by rituals, by being part of the 'in crowd' - all of which is offered us in false religion. If the Christians in Galatia, or in Stranraer or wherever do this, then Paul may well despair that his labours have been in vain.

So any Christian reading this - time for self reflection and examination: where do you find, in your religious life, that you are depending upon days, seasons, rituals, ceremonies - which you know have become a false god to you? What is tempting you in this direction? How can we encourage one another to remain in the gospel now that we have come to know God?