Nothing is a greater robber of joy than WORRY. From a spiritual standpoint, worry is wrong thinking (the mind) and wrong feelings (the heart) about circumstances, people, and things.
The antidote to worry is the secure mind: “And the peace of God…shall keep [garrison, guard like soldier] your hearts and minds through Christ Jesus!”
When you have the secure mind, the peace of God guards (v. 7) you and the God of peace guides you (v. 9).

The antidote to worry is the secure mind: “And the peace of God…shall keep [garrison, guard like soldier] your hearts and minds through Christ Jesus!” When you have the secure mind, the peace of God guards (v. 7) you and the God of peace guides you (v. 9). With that kind of protection – why worry?

Paul’s spiritual mind has him heartbroken over the way some professed Christians are living, people who “mind earthly things.” In this section, Paul is encouraging us to have the spiritual mind because our citizenship is in heaven. Philippi was a Roman Colony on foreign soil. It much the same way, we are citizens of a heavenly colony on earthly soil. We need to live now as if we were living in our future home.

This text is not talking about salvation. That would contradict what Paul previously said in chapter 3. Paul is talking about being a “winning Christian” - one who fulfills the purpose for which he was saved.

What are the essentials for winning the race and one day receiving the reward that is promised?

We must be dissatisfied, devoted, directed, determined, and disciplined

The spiritual mind is set on heavenly things not earthly things. It is a mindset that takes a heavenly perspective, not an earthly perspective. A saved person can have either an earthly mindset or a heavenly mindset. The spiritual mind keeps things from robbing you of joy.

Christ shows us the pattern for the submissive mind. Paul reveals to us to power for the submissive mind. And Timothy and Epaphroditus give us the proof that we too can have the submissive mindset.

If we're going to live out the great example of Christ's submissive mindset then we must know that there is a purpose to achieve, a power to receive, and a promise to believe. We can't do it by imitation; we must do it by incarnation.

Chapter 1 focused on the "single mind." Chapter 2 focuses on the "submissive mind."
The submissive mind puts others first for the glory of God.
The secret of joy in spite of circumstances is the single mind.
The secret of joy in spite of people is the submissive mind.
Jesus is our ultimate example of a person exercising the attitude of humility found in the submissive mindset.

In our text, Paul is speaking about fighting for the faith of the Gospel. The “faith” is the same thing that Jude mentioned in Jude 3 – “Earnestly contending for the faith.” (cf. 1 Tim. 4:1)
We must earnestly fight for faith and strive for the advancement of the gospel so that we can hand the baton of the faith of the Gospel to the next generation.