Obadiah was over the household of Ahab during his reign as King of Israel, a position perhaps equivalent to a chamberlain. While Ahab and his queen, Jezebel, worshipped Ba'al and Asherah and persecuted followers of Yahweh, Obadiah remained faithful to the LORD. When widespread execution of God's prophets began, Obadiah hid 100 of them in two caves.
A Follower of Yahweh
No information about Obadiah exists outside of his brief appearance in Kings acting as a messenger to Ahab for Elijah and a servant of God. Obadiah would have lived in the capital of Samaria in the famous ivory palace. He would have been intimately involved with the affairs of Ahab's life, managing Ahab's personal life alongside his family in contrast to his government duties.
By his own admission, Obadiah had worshipped Yahweh since boyhood. Presumably he was raised in a devout Hebrew family who worshipped the God that his ancestors had worshipped.
The narration introduces Obadiah as the Head of Ahab's household, a devoted follower of Yahweh who hid the prophets from persecution. Apparently, Jezebel had been using her position as queen to destroy any and all worship of Yahweh in the Kingdom of Israel, instead advocating for a national worship of Ba'al and Asherah.
When Obadiah saw the damage that Jezebel would do to the worship of God in his country, he secretly stowed away one-hundred prophets of Yahweh. He hid half of the prophets in one cave, the other in another cave. Using the resources available to him as the King's Chamberlain, he kept all of them sustained with food and water. Undoubtedly, if Jezebel had discovered Obadiah's work against her eradication of Yahweh worship, he would have been executed as well.
An Encounter with Elijah
Due to Ahab's work against God, Elijah declared a famine across the land. When Ahab saw that the drought was affecting his horses and mules, he summoned Obadiah. Being responsible for all matters pertaining to his master's household, Obadiah was asked to search throughout Israel grass that could feed Ahab's animals. While Obadiah searched in one part of the land, King Ahab searched in another..
As Obadiah was searching the land for living grass and a supply of water, Elijah sought him out. When Obadiah encountered Elijah, he recognized him and bowed in reverence. Obadiah had now met Yahweh's chief agent in Israel, a fellow ally in preserving the enduring worship of the true God against the powerful machinations of the royal family. 
Since Obadiah would had been the household representative for Ahab, Elijah asked him to notify Ahab of his whereabouts. At first, Obadiah protested- believing Elijah travel on the Spirit's leadings, Obadiah feared that if he gave a false report of Elijah's whereabouts, he would be executed. Ahab had dedicated troves of men to scouring the country and beyond for Elijah's person. Obadiah explained how he had worshipped Yahweh since his youth and how this trust in God was demonstrated through hiding one-hundred prophets. Still, Elijah insisted that he would meet with Ahab. 
Elijah is Here
Obadiah obliged, going to meet Ahab and notifying him that Elijah had requested an audience with him. .