Thursday is represented by the Green Flame. This flame is green like moss with golden radiation. This ray brings into one's Being Divine qualities of Truth, Dedication, Concentration and Healing.
Invocation for Thursday
"Tenderly Beloved Presence of God, I AM in my self. I invoke Thy Green Flame of Truth and Healing, I dedicate my life now and forever to serving of God, serving the Good, so that from now on my brain thinks only what is perfect, that my feeling remains calm, full of love, caring, ready to help and be happy, that my hands only bless and heal, that my legs be only messengers of the good, that my body be strong and willing to be an instrument of help, carrying everywhere God's Perfection.
When we seek divinity, health, happiness and abundance and if we would before that understand the meaning and power of constantly sustained attention, and then in conscious effort withdraw the attention from all phenomena in the world and anchor it in God's Presence, its return action would flood us with the fullness of everything we could desire."
Note: This is only a shortened version of the Thursday Invocation!
You can also directly invoke the help of Archangel Raphael and Elohim Vista, who are responsible for the energies and qualities of the Green flame and for the Fifth ray in general.