As Paul begins chapter four, he begins with a summary statement, giving some final exhortations to the instructions he has shared in the previous passages, before moving on to some final thoughts.
You can see this encouraging verse in Philippians 4:1:
All of the previous information, concerning those who live for Christ, as well as those who are enemies of the cross, serves to encourage the believers in Philippi to stand firm. In doing so, he uses several terms of endearment and displays just how much he loves the church and people in Philippi.
The main message of this verse is for the Philippians to stand firm. However, there is much more in this simple-seeming verse than first appears. Paul shares a lot of information in these few short words. As he gives this exhortation, he shows just how critical it is for believers to stand fast, and not be swept away by sin and worldly desires.
Some have tried to connect this passage to the content coming in chapter 4, and this is seen clearly in the re-translation found in the NIV2011. However, the context of the passage itself leads us to understand that this is more in reference to the preceding passages. This is seen most clearly by the use of the word “therefore,” giving us reasons to stand firm.
We stand firm because Christ is powerful (3:21). We stand firm because he will transform us into new creations when the dead are raised (3:21). And we stand firm because our citizenship is found in heaven (3:20).