A few gospel quotes against signs and proselytizing:
"When an impure spirit comes out of a person, it goes through arid places seeking rest and does not find it. Then it says, 'I will return to the house I left.' When it arrives, it finds the house unoccupied, swept clean and put in order. Then it goes and takes with it seven other spirits more wicked than itself, and they go in and live there. And the final condition of that person is worse than the first. That is how it will be with this wicked generation." (Mat 12:43-45 NIV)
The 'Impure spirit' appears driven out (by signs) but returns in a worse way. So this is spoken against all of those "Jesus statue bled" kinds of arguments and "I was healed by Jesus so believe in Jesus." These are all proselytizer methods. I also put creationism arguments in this category -- all the garbage that doesn't result in real spiritual fruit.
And he spake a parable unto them, Can the blind lead the blind? shall they not both fall into the ditch? The disciple is not above his master: but every one that is perfect shall be as his master. And why beholdest thou the mote that is in thy brother's eye, but perceivest not the beam that is in thine own eye? (Luk 6:39-41 KJV)
That is part of a rant Jesus makes against discipleship methods. He, himself, tells his disciples that he doesn't use this method but will be sending them the spirit of truth to fill in the blanks. Jesus doesn't think that one person should disciple another or that there can be improvement by this means. He says disciples can only be as good as or worse than their masters. He reinforces this many times in the gospels, though you won't hear any backstabbing preachers comment on it. They're all pretty terrible in my experience, often not even knowing it; sometimes relishing it.
"I have much more to say to you, more than you can now bear. But when he, the Spirit of truth, comes, he will guide you into all the truth. He will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come. He will glorify me because it is from me that he will receive what he will make known to you." (Jhn 16:12-14 NIV)
For I say unto you, That except your righteousness shall exceed [the righteousness] of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven. (Mat 5:20 KJV)
This is part of Jesus denouncement of the master-disciple scheme. He doesn't trust it, and he overall says you have to do better than any human master can make you. To do that you can't train under a human. He defenestrates master-disciple for his disciples.
There is plenty more of this material in the NT. James is a book highly critical of those who put emphasis upon wealth and education and who would give preferential seating to wise people. It is a book packed with great quotes on this subject and only 5 chapters long. Paul, too, makes speeches about it in his letters.