"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? 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" Matthew 16:11-12.
Jesus once said to his disciples; "How is it that ye do not understand that I spake?" And to address the problem he said "ye should beware of the leaven..."
Here this my friend; you can only hold one religion at a time, not two, but "One Lord, one faith, one baptism,"(Eph 4:5). Once you’ve been indoctrinated with a belief then that's it - you're done. You'll have no more room for any other religion - you can now not serve two masters. Jesus said beware of yeast because as a fermenting agent it has the potential to cause disease, and "... no man putteth new wine into old bottles; else the new wine will burst the bottles, and be spilled, and the bottles shall perish" (Luke 5:37). You're that vessel which needs to beware what's put in you.
I'm afraid though for some of us who are full-up of the old such that we have no room for the new. You need to go through a process of detoxification in order to have a new fresh anointing. Hebrews 5:12 says, "For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat."
The word you've heard over the years is like food consumed that can putrefy and produce toxins that can harm the body, and to detox is the only way to rid your spirit, soul and body of those undesirable elements in your walk with God. No way you will be able to handle the new wine in the same status quo.
The disciples couldn't understand because of bad "toxins" they'd accumulated from the Pharisees. Each time he would teach them they would cross reference with the Pharisees.
So Jesus had to detox them, "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." Some believers don’t understand when I we teach, Beware of false teachers and false prophets.
But the disciples later realised how bad Pharisees habits were when they started to hold on to a single faith. False prophets are a harmful batch of individuals that allegedly exert undesirable effects and unbelief among others.
"Take heed therefore that the light which is in thee be not darkness" Luke 11:35. You find Pharisees everywhere, Proverbs 30:28 says, "The spider taketh hold with her hands, and is in kings' palaces." Beware!
"Wherefore be ye not unwise, but understanding what the will of the Lord is. And be not drunk with wine, wherein is excess; but be filled with the Spirit; Speaking to yourselves in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord; Giving thanks always for all things unto God and the Father in the name of our Lord Jesus Christ; Submitting yourselves one to another in the fear of God" Ephesians 5:17-21. Get rid of the old wine, but be filled with the Spirit if indeed you want to know/understand what the will of the Lord is for your life.
www.muzembi.org - Simple Gospel Summation.