Here is a quote from Ellen G. White that specifically talks about a green cord:
“My guide now opened the door, and we both passed out. He bade me take up again all the things I had left without. This done, he handed me a green cord coiled up closely. This he directed me to place next my heart, and when I wished to see Jesus take it from my bosom and stretch it to the utmost. He cautioned me not to let it remain coiled for any length of time, lest it should become knotted and difficult to straighten. I placed the cord near my heart and joyfully descended the narrow stairs, praising the Lord and joyfully telling all whom I met where they could find Jesus. This dream gave me hope. The green cord represented faith to my mind, and the beauty and simplicity of trusting in God began to dawn upon my benighted soul.”
In this context, the green cord represents faith.
References:
- White, E. G. (1945). Early Writings, p. 81.1.
- White, E. G. (1915). Life Sketches, p. 35.3.
- White, E. G. (1855). Testimonies for the Church, vol. 1, p. 29.1.