I'm reading through the book of Jeremiah right now. He was known as the weeping prophet, and for two reasons that I can think of. First, his success rate was near "zero"! -- if you count success as the people to whom he was sent actually listening to his
message, repenting and avoiding the disasters he was predicting. Second, he not only was denied the privilege of marrying and having children, but he had to ride through every disaster that befell the people. And even though the Chaldean commander was lenient with him and allowed him to return, thus providing a ray of hope and light in his life, the remnant that was left still refused to listen and comply, and hauled him off with them to Egypt where he presumably died!
If ever there was a man who achieved the exact opposite of what we would define as "success", it was Jeremiah! How in the world did he keep going?! Most humans I can think of, including myself, would probably have given up a long time ago.
But Jeremiah kept going. Not because the people were listening and turning from their sin, but simply because God told him to! And, God was with him all the way! God was communicating with him on a regular basis. He was the shield that protected Jeremiah from the onslaught of the evil people of his day. His walk was continually uphill, but God was the one who gave him the strength to carry on.
Jeremiah's life provides a huge example for us today. God wants us to follow Him and be obedient. Jeremiah was successful not because he achieved the goals of his message, but simply because he continually was obedient to his calling! He was successful in the eyes of God!