Maybe God created happiness for us to feel when things work out for us, and joy for us to feel when the kingdom of God is at hand.

Read these lyrics in that light. The writer thinks having Jesus come and be our King is the primary reason for our rejoicing:

Joy to the world, the Lord is come
Let earth receive her King

Joy to the earth, the Savior reigns

He rules the world with truth and grace

Having God come to earth and be our King is the best news ever. It’s worth celebrating and singing and smiling and rejoicing.

I searched the New Testament for occurrences of joy and rejoicing. I think all of the hundred verses are a response to the coming the kingdom of God.

For the kingdom of God is not a matter of eating and drinking, but of righteousness, peace and joy in the Holy Spirit – Romans 14:17

But the fruit of the Spirit is love, joy, peace,... – Galatians 5:22

Joy is what we feel when we see signs of the kingdom:

• hear the word of the kingdom – Mt 13:20, Mk 4:16, Lk 8:13
• find the kingdom – Mt 13:44
• Jesus is risen – Mt 28:8
• Jesus is coming to be King – Lk 1:14, Lk 1:44
• the kingdom is revealed – Lk 10:21
• lost are saved – Lk 15:5, Ac 16:34
• see miracles, healing and deliverance – Lk 19:37, Ac 8:8
• see Jesus – Lk 24:41, Lk 24:52, Jn 16:20-22
• abide in God’s love – Jn 15:11
• answered prayer – Jn 16:24
• God’s presence – Ac 2:28, Ac 13:52
• Spirit’s filling – Ro 15:13
• enduring suffering – 2 Co 7:4, 2 Co 8:2, 1 Th 1:6, Jas 1:2
• praying – Php 1:4
• unity in Christ – Php 2:2
• hospitality in the Lord – Php 2:29
• thanksgiving – Col 1:2

Joy is the appropriate response for these things and many more. It doesn’t mean everything is working out for us. We might not be happy. We could be in a lot of pain. But the kingdom of God is coming! We can have joy.

Though you have not seen him, you love him; and even though you do not see him now, you believe in him and are filled with an inexpressible and glorious joy – 1 Peter 1:8

To him who is able to keep you from stumbling and to present you before his glorious presence without fault and with great joy – Jude 1:24

When you see, hear or sense something of the kingdom, go ahead and be joyful. Let yourself believe enough to enjoy the moment. Choose joy. Feel the joy. Receive the coming kingdom with joy.

I think I’ve listened to this song 100x in the past few days, just revelling in the joy.