Matthew 16:11-12 (KJV)
11 How is it that ye do not understand that I spake it not to you concerning bread, that ye should beware of the leaven of the Pharisees and of the Sadducees?
12 Then understood they how that he bade them not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees.
The religious leaders at the time of Jesus Christ taught things that were contrary to the Word of God and it’s intent. For example “Matthew 15:1-9 (KJV) Then came to Jesus scribes and Pharisees, which were of Jerusalem, saying, [2] Why do thy disciples transgress the tradition of the elders? for they wash not their hands when they eat bread. [3] But he answered and said unto them, Why do ye also transgress the commandment of God by your tradition? [4] For God commanded, saying, Honour thy father and mother: and, He that curseth father or mother, let him die the death. [5] But ye say, Whosoever shall say to his father or his mother, It is a gift, by whatsoever thou mightest be profited by me; [6] And honour not his father or his mother, he shall be free. Thus have ye made the commandment of God of none effect by your tradition. [7] Ye hypocrites, well did Esaias prophesy of you, saying, [8] This people draweth nigh unto me with their mouth, and honoureth me with their lips; but their heart is far from me. [9] But in vain they do worship me, teaching for doctrines the commandments of men.”
Noting has changed. Today we also have religious leaders causing deception. In many of the epistles of the New Testament we are also warned to not be deceived and to be on guard and watch. As the time of the return of Jesus Christ our LORD is coming closer  demonic activity and deception will increase. Jesus even warned us “Matthew 24:23-24 (KJV) Then if any man shall say unto you, Lo, here is Christ, or there; believe it not. [24] For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect.”. How do we protect ourself from deception? By drawing closer to Jesus Christ, praying, reading, studying the Word of God, gathering with bothers and sister…. Let us be wary of the lates fads “2 Timothy 4:3-4 (KJV) For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears; [4] And they shall turn away their ears from the truth, and shall be turned unto fables.” and examine them in light of the bible knowing how to “2 Timothy 2:15 (KJV) Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.”
Therefore be encouraged as it is written in 1 John 3:7 (KJV) “Little children, let no man deceive you: he that doeth righteousness is righteous, even as he is righteous.”. Let us as it says in 1 Corinthians 16:13-14 (KJV) “Watch ye, stand fast in the faith, quit you like men, be strong. [14] Let all your things be done with charity.”

NOTE: For more on this have a look at other devotions like:
“Antichrists – 2024.09.22 https://missioncommunities.network/2024/09/22/antichrists-2024-09-22/” and “Discernment of false signs and wonders – 2024.06.07 https://missioncommunities.network/2024/06/07/discernment-of-false-signs-and-wonders-2024-06-07/”