You've heard it said that happiness is dependent on your circumstances but joy is not. The Bible doesn't teach this. Every time you see someone rejoicing (the verb form of joy) in Scripture, it is in response to circumstances. But joy takes a BIG view of circumstances, so that while we may be behind on bills, we don't limit our focus to that negative circumstance, but also include the grand, glorious and wonderful circumstance that Christ is risen. And so we are able to rejoice in the midst of the negative because of the greater positive. Infinity plus negative seven is still infinity!
The resurrection of Christ may not be THE foundational circumstance for our joy, but it's got to be one of them. In Matthew 28:8, the women left the tomb with great joy! And they were running to share the news. Oh God, let me always remember the resurrection! Let me live in its power! Let me run with the news!
Mark 4:16-17 shows how tenuous this can be. We can receive the word with joy, yet stumble when pressure or persecution comes. Lord, we need roots! But what does this mean? With a quick scan of Bible verses, but without doing any serious study, I am thinking that having roots is a result of consistent abiding in Christ and in His word. It is not enough to "receive" the word with joy once. We need to be receiving the word on a daily basis, trusting in the Lord on a daily basis, so that we become like the tree planted by streams of water, with roots deep and strong. With these roots, come what may, our negative circumstances will never overwhelm our awareness of the positive circumstances of the resurrection, our salvation, the faithfulness of God and more!