A strange repeated command
On the surface of it, "Rejoice in the Lord always, again I say rejoice" is a strange command (Philippians 4:4).
How can one command joy? What if the circumstances we find ourselves in are anything but joy bringing? Are we expected to find and flick a joy switch? And if so wouldn't that joy be false?
Is Paul encouraging us to a stoical kind of joy, a grit-your-teeth kind of joy? An outward joy that does not reflect our hearts or are circumstances?
The commands of Scripture do not pass straight to the will or emotions but run through the mind - a mind that is informed by God's Word and God's promises.
So here are three steps - mental steps, mind steps, Word steps, to joy, when we find ourselves in the dumps:
(1) Trust in the over-ruling providence of God
We often find ourselves joyless when something 'bad' has happened - something we have labelled 'bad'. In these circumstances, we get ourselves back on the joy track by remembering that even that thing is included in the "all things" of Romans 8:28 which will work out for our good. So we rejoice in the sovereign purposes of God, though we cannot see them.
(2) Trust in the forgiveness of God
On other occasions we are joyless because we have fallen - once again - into something we hate and thought was once history. Condemnation sets in and we spiral into guilt and remorse. Joy returns when the promise of God to forgive us if we confess our sin comes to mind.
(3) Remember the Father's unconditional love
A third step to joy is to remember that we are unconditionally loved by God, covenantally loved by him, no matter what or how or when.
The fruit of the Spirit, which is joy, is not disconnected from the work of renewing our minds with God's Word. It's not as if joy can just well up if condemnation fills our minds and hearts. Removing these hindrances to joy "allows" the joy of the Holy Spirit to bubble up, the joy inexpressible and full of glory.