One of the characteristic of spiritual disciplines is that they are activities. They are not attitudes. Disciplines are practices. Spiritual disciplines are things you do. They are not character qualities. They are not graces. They are not the fruit of the Spirit. They are things you do.
So you read the Bible. That is something you do. That is a spiritual discipline. You meditate on Scripture. Your pray, fast, worship, serve, learn, and so forth. These are activities. Now the goal of practicing any given discipline is not about doing as much as it is about being: being like Jesus, being with Jesus. But the biblical way to grow in being more like Jesus is through the rightly motivated doing of the biblical, spiritual disciplines.
The key verse in all this is
1 Timothy 4:7, which says, “Discipline yourself for the purpose of godliness” (NASB). The goal is godliness, but the biblical means to that is to discipline yourself by the power of the Holy Spirit rightly motivated. We are to discipline ourselves for the purpose of godliness. The practical ways of doing that are things that you do.
Strictly speaking, joy is not a spiritual discipline. That is the fruit or the result of discipline done rightly. So it is that distinction between doing and being. And the spiritual disciplines are about doing. You can do them as a Pharisee. You can do them wrongly motivated. But rightly motivated, they are things that we are to do in order to be like Jesus, to be with Jesus.