Because the foolishness of God is wiser than men; and the weakness of God is stronger than men. For ye see your calling, brethren, how that not many wise men after the flesh, not many mighty, not many noble, are called: But God hath chosen the foolish things of the world to confound the wise; and God hath chosen the weak things of the world to confound the things which are mighty; 1Co 1:25-27
Such is the simplicity od the Gospel. Men to today try as they might can't change the simple written word of God. Those who falsely teach doctrines of men twisting the word of God to try and justify their made up beliefs become fools in so doing.
Folks, I implore you to do several things so that you will not be taken in by these heretics. First, learn God's plan of salvation and implement it in your life and teach it to others.
Second, follow the instructions in 2Ti_2:15 Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.
Third, be as those in Berea, Act 17:11 These were more noble than those in Thessalonica, in that they received the word with all readiness of mind, and searched the scriptures daily, whether those things were so. YOU, make sure what is being taught is right according to scripture. Do NOT just take the preacher's word for it!
You need to understand ONE thing God gave instruction to us via His word. If it could not be understood the same way by all, then God would be a liar. Men have so twisted God's word that the simplicity of the Gospel and the simplicity of the apostle's teaching's are now claimed by these false teachers as foolishness.