Adam Clarke on John 14:26

He shall teach you all things - If in the things which I have already spoken to you, there appear to you any obscurity, the Holy Spirit, the Advocate, Counsellor, and Instructer, will take away all your doubts, free you from all embarrassment, and give you a perfect understanding in all things: and this Spirit ye shall shortly receive.

And bring all things to your remembrance - Here Christ promises them that inspiration of the Holy Spirit which enabled them not only to give a true history of his life and death, but also gave them the most perfect recollection of all the words which he had spoken to them, so that they have been able to transmit to posterity the identical words which Jesus uttered in his sermons, and in his different discourses with them, the Jews, and others.