The following is taken from the 16th century text titled Treasury by St. Damaskinos the Studite.
The Jordan River had done many miracles and was full of grace, sanctified, and this is why Christ went there.
One miracle related to the Jordan River is when Joshua the son of Nun came to it with the twelve priests who carried the Ark of the Covenant, and by the command of Joshua the priests entered with the Ark. Then a strange miracle took place: the Jordan stopped its flow and only enough water remained that the ankles of the priests alone became wet. The water remained this way until all the Jews passed through.
Another miracle is when Elijah the Prophet passed through the Jordan with Elisha, again as if on dry land, after the Prophet Elijah "struck" the river with his sheepskin mantle and a path was opened for them, which they walked without getting wet. After this Elijah ascended into the heavens with a fiery chariot drawn by four horses, and he left his sheepskin mantle behind for Elisha. Elisha proceeded to "strike" the waters of the Jordan again in order to return from where he came, but nothing happened. Then he invoked the God of Elijah and immediately the wondrous event was repeated.
Yet another time the general of the King of Syria named Naaman had leprosy and went to the Prophet Elisha to be healed by him. But Elisha did not meet with him, rather he told him to go bathe in the Jordan River to be healed. At first he was angry by this response of the Prophet, but in the end he was obedient and indeed became completely well.
Once certain woodcutters went to the bank of the Jordan to chop wood, and among them was the Prophet Elisha. As they were cutting wood the iron axe became detached and fell into the river. Then the Prophet took the wooden handle and touched the edge of the river, saying: "Show a miracle, my God." Immediately the iron part sprung up from the river and entered the handle, forming the sign of the Cross.
In one hymn of Saint Kosmas the Melodist this miracle is mentioned as foreshadowing Holy Baptism as well as the Honorable Cross: "Jordan received into its deep bosom a sharp axe, and then was forced by a stick of wood to give it back again, thus betokening the cutting of error by the Cross and Baptism." Jordan, which received the cutting iron, returned it to the wood, and just as an axe cuts wood, so also the power of the Cross and Baptism cut away error and sin.
Many other miracles took place there, such as when Gideon the Judge passed through it, as well as Jacob the son of Isaac and brother of Esau who passed through it with his staff, as he himself says: "With my staff I crossed this Jordan."
Source: Translated by John Sanidopoulos.