These two verses are taken from the Kūrma Purāṇa.
When Lord Ramacandra tested the body of Sita, it was the false, illusory Sita that entered the fire. At that time the fire-god brought the original Sita from his abode and delivered her to Lord Ramacandra
Expressions researched:
"When Lord Rāmacandra tested the body of Sītā, it was the false, illusory Sītā that entered the fire. At that time the fire-god brought the original Sītā from his abode and delivered her to Lord Rāmacandra"
Sri Caitanya-caritamrta
CC Madhya-lila
“When he was petitioned by mother Sītā, the fire-god, Agni, brought forth an illusory form of Sītā, and Rāvaṇa, who had ten heads, kidnapped the false Sītā. The original Sītā then went to the abode of the fire-god. When Lord Rāmacandra tested the body of Sītā, it was the false, illusory Sītā that entered the fire. At that time the fire-god brought the original Sītā from his abode and delivered her to Lord Rāmacandra.”.
“When he was petitioned by mother Sītā, the fire-god, Agni, brought forth an illusory form of Sītā, and Rāvaṇa, who had ten heads, kidnapped the false Sītā. The original Sītā then went to the abode of the fire-god. When Lord Rāmacandra tested the body of Sītā, it was the false, illusory Sītā that entered the fire. At that time the fire-god brought the original Sītā from his abode and delivered her to Lord Rāmacandra.”