Ephesians 2:11 Don’t forget that you Gentiles used to be outsiders. You were called “uncircumcised heathens” by the Jews, who were proud of their circumcision, even though it affected only their bodies and not their hearts.
Colossians 2:4,8 I am telling you this so no one will deceive you with well-crafted arguments. Don’t let anyone capture you with empty philosophies and high-sounding nonsense that come from human thinking and from the spiritual powers of this world, rather than from Christ.
observation
We have all seen the Peanuts TV special “It’s the Great Pumpkin Charlie Brown,” Linus is trying to convert his friends into believers of “the Great Pumpkin.” Linus writes a letter to the Great Pumpkin, to Charlie Brown's disbelief, Snoopy's laughter, Patty's assurance that the Great Pumpkin is a fake, and even to Lucy's violent threat to make Linus stop ("You better cut it out right now or I'll pound you!").
But Linus is convinced that the Great Pumpkin will indeed come because he thinks the patch he's in is sincere enough and even convinces Sally to stick around to wait with him. But then later Sally gets mad because she has missed “tricks or treats” and a big party at Violets house and then she threatens to "sue" Linus. She storms out of the pumpkin patch with the other kids, leaving Linus by himself, still convinced the Great Pumpkin will come.
Paul warns us of the deceived people in the temple, he talked about those religious looking people, the posers that want to convert you to their way of thinking. Being sincere is a very common trait amongst the deceivers, the thing about being deceived is that by definition of the word, you don't know that it has happened to you. We have to be careful for deceivers and we have to make sure that aren't one of them.
Titus 1:10 For there are many rebellious people, mere talkers and deceivers, especially those of the circumcision group.
I am sure that the religious leaders that killed Jesus were very sincere and those same leaders were still sincere when the disciples started teaching about Jesus and they were still sincere when they stoned Stephen and martyred almost every one of the original disciples.
application
I must be careful that I am obedient and that I am not being religious, I want to be the real deal, I don’t want the person that people see to really be a fake that is stirring up trouble, Jesus wants his disciples to spread the good news of the gospel without any personal motives or deception added on.
prayer
I pray that I will be genuine and that you will find me faithful to the mission that you have given me. Help me to follow your commands without the disguise of being religious.