What is the “key of knowledge” referred to in `Luke 11:52`, where the Lord Jesus said to the Scribes and Pharisees “Ye have taken away the key of knowledge; ye entered not in yourselves, and them that were entering in ye hindered?”

Some one has said "The summary want of the age is that last philosophy into which shall have been sifted all other philosophy, which shall be at once catholic and eclectic, which shall be the joint growth and fruit of reason and faith, and which shall shed forth through every walk of research the blended light of discovery and revelation." The Bible is just such a revelation and contains that true philosophy which is the basis for all philosophies. It is the "key of knowledge," the Standard of Truth, and all lines of investigative thought which ignore this Standard and are contrary thereto, are "vain philosophies and science falsely so-called." (`1 Tim. 6:20`.) The "lawyers," Doctors of the Law, the Doctors of Divinity of our Lord's time, had made void the Word of the Lord through their traditions and speculations. (`Mark 7:13`.) The people, looking to these "lawyers" for true instruction regarding the Lord's Word, were deceived and confused by their false teachings.