Sometimes they are peers, or elders, or respected friends.
They deny God exists. They tell you that He does not love you. They tell you that truth isn't desirable because it can hurt. They make you feel worthless, or lost, or alone, because you have the things that they desire. Things like love, honesty, and faith.
They make good things like morality and caring about others seem as if they are foolish or terrible. These people are vain, proud, uncaring, and deceitful. They have become as Peter said, the "servants of corruption". And the hardest thing about it is, they often don't even realize they are doing it.
Sometimes all it takes is a small comment. The undermining of your self-esteem, or the claim that God is punishing your loved one or letting them suffer from illness or grief. The idea that God is vengeful and would purposely inflict pain upon anyone is false. He is the relief from all pain! It is when we are disobedient, ignore him, and try to stand on our own that we suffer most.
If anyone's words seem to undermine your faith in God, or make you question your strongly held love for your Savior, then that person is a false teacher.
Let me make this abundantly clear: God loves YOU. He cares for you with every part of his being. You are his. Every trial that you suffer through is one that will mold, define, and grow you. He doesn't like watching you hurt, and would take much of the burden of pain from you if you let him. He can even do this by sending wonderful people into your life to listen to and comfort you. His love can be a balm to your soul; a safe haven from worldly pain.
Turning away from God... listening to these falsehoods from Satan that convince you that he doesn't love you... they are all a trap. They are dragging you down into the mire after you have worked so hard to clean yourself free of the mud that lies there.
Sometimes life seems so very hard. You just want to give up, and the voices all around you are telling you that you cannot possibly succeed because they have already failed. You have already risen above the dark muck of the world and are on a path to safety, when those voices try to tug you down again. If they succeed, and you succumb to the darkness again, then you will be lost. God can only pull you out if you keep reaching for him. So don't give up!
Christ's atonement can free you of your sins, but only if you allow him to. He will help you turn from addiction and habitual sins, but if you keep turning back to them you will fail. If you mess up, however, you CAN return to Christ's loving arms. He will ALWAYS have them stretched out towards you. Don't forget that. And getting a few splashes of mud on you when you are trying to struggle free of the mire is expected. You might even fall back in by accident when you are struggling so hard to pull yourself out. Just remember that you can ALWAYS get back up and try again.
Don't give up. God's here for you. I'm here for you. You can do it!