Wesley believes that God is Great as well as Good. This is important because greatness by itself has no moral component: greatness could be amoral or even immoral. One can be great in power and have no moral feature to the use of power.
For Wesley the notion of goodness is what informs an understanding of God's power. God's Greatness and power are expressed in His Goodness.
This understanding of God's Greatness expressed in Goodness means that all attributes of God are to be understood as manifestations of God's love. In other words, God's justice is not simply justice but justice informed by love. God's omnipotence is not just omnipotence but omnipotence informed by love.
I believe this keeps us from a "yeah, but theology." This is when we seem to pit attributes of God against each other. For example, God is omnipotent, yeah, but he is also merciful. Wesley's view of all of God's attributes are informed or manifestations of God's Holy Love.
REFLECT: Is your view of God where all his attributes are informed by His Goodness? If not, why not?