The word "Christian", is the English Translation of the Greek "Χριστιανός", which meant "Christ-Like" or "Belonging to Christ" or as it is also written, being a slave or prisoner of Christ. The word, used only twice in the entire NT, was used to describe the Apostles because they "walked like" or "yielded themselves" under the same way of Life that the Christ "of the Bible" walked in. This included, as Paul teaches, "Yielding themselves" a servant to obey God, as the Jesus "of the Bible" did, and becoming servants of "God's Righteousness", not the philosophies, doctrines and traditions of this world's religious sects and businesses they were born into.
But even then, this same Christ warned about religious men, who called Him Lord, Lord, which means they "claimed" to be "Christians", but they were not "doers" of His Sayings. (they honored Him with their lips) These self-proclaimed "Christians" who called the Lord's Christ, their Lord, (Matt. 7:21) they would teach in His Name, they would help people, poor and sick, in His Name, create huge religious businesses, all in His Name, but because they lived a lifestyle which rejected many of the judgments, commandments and Statutes of the God and Father of All, Something the Lord's Christ, or His Disciples didn't do, He said HE doesn't know them. The Scriptures speak to this as well.
1 John 2:
6 He that saith he abideth in him (Call's Jesus Lord, Lord) ought himself also so "to walk", even as he walked. The man who "presses toward the Prize of this calling" (Phil. 3:14), would be a "Christian", as defined by scripture, in my view.
The Jesus "of the bible" speaks to these "many" in Matt. 6., as men who frequent manmade shrines of worship, made of wood and stone called "Synagogues" (ναός, οῦ, ὁ) (a temple, a shrine, that part of the temple where God himself resides), and building these manmade structures for their god to reside in has been a tradition of this world's religions for a long time, perhaps as far back as the Tower of Babel.
The Bible teaches that God doesn't reside in temples made of wood and stone, and therefore HE pointed out, through His Son, that those who frequent them, do so to be seen of other men, not God. HE goes on to instruct "Christians" how to pray and do alms. Neither Jesus, nor those who walked like HE did, in the examples shown in the New Testament, built or promoted the building of these manmade shrines of worship.
I'm not sure it really matters what the difference is between Pharisees and the Sadducees, as they both "
profess that they know God; but in works they deny him, being abominable, and disobedient, and unto every good work reprobate".
Therefore, it doesn't make much sense to debate the difference between a man from one "Christian" religious sect or business of this world, from another "Christian" religious sect or business of this world, if they both transgress God's commandments by their own religious traditions. According to the Lord's Christ Himself, there are 2 kinds of "Christians".
Those who "Hear" His Sayings, and "DO THEM", and those who hear His Sayings, and "DO THEM NOT".
I advocate that men deny themselves, and become a "Doer" of His Sayings, and not a hearer only. That men should strive to enter this Path, followed by the Few, and not the other, followed by the "many".