You may be getting discouraged because you know you're doing what the Lord has told you to do, but you don't see any results. You've been faithful, but you're getting weary. Let me share a story that will encourage you:
A man was sleeping at night in his cabin when suddenly his room filled with light and the Savior appeared. The Lord told the man he had work for him to do and showed him a large rock in front of his cabin. The Lord explained that the man was to push against the rock with all his might. The man did, day after day. For many years he worked all day, with all his strength, his shoulders set squarely against the cold, massive surface of the unmoving rock. Each night the man returned to his cabin sore and worn out, feeling that his whole day had been a huge waste.
Since the man was showing sign of discouragement, Satan took advantage of his weakness and put thoughts into the man's mind: "You've been pushing against that rock for a long time, and it hasn't budged. Why kill yourself over this? You're never going to move it." He only reinforced the man's impression that the task was impossible and that he was a failure. He began to despair and thought, "Why kill myself over this? I'll just put in my time with minimal effort, and that'll be good enough."
That was his plan until he thought that he'd pray about it one more time. He stood and pleaded, "Lord," he said, "I've worked long and hard serving you, putting all my strength into doing what you asked me to do, yet after all this time, I've not even budged that rock by half a millimeter. What's wrong? Why am I failing? What am I doing wrong?"
The Lord asked him to sit down and rest, and in a voice filled with compassion said, "Son, when I asked you to serve me and you accepted, I told you that your task was to push against the rock with all your strength, which you have done. Never once did I mention to you that I expected you to move it. Your task was to push. And now you come to me, exhausted and worn out, thinking that you've failed. But this isn't so. Look at yourself. You're arms are strong, and your muscles have grown solid and defined. Your legs are powerful, your back is sinewy, and your hands are callused from constant pressure. You've become powerfully built.
"Through resistance you've grown so much, and your abilities now surpass what you could ever do before. Yet you haven't moved the rock. But your calling was to be obedient and to push and to exercise your faith and trust in My wisdom. This you have done. Son, I will move the rock."
At times when we hear a word from God, we tend to use our own intellect and end up misunderstanding why the Lord wants us to do what He's called us to do. Many times what He wants is simple obedience, faith and trust in Him.
So, your faith may move mountains, but it's still God who moves the mountain. If the mountain doesn't move, faithfully serve Him until He tells you to move on.
"When you obey me you should say, 'We are unworthy servants who have simply done our duty.' " Luke 17:10