Mark 7:6-7 English Standard Version

And he said to them, “Well did Isaiah prophesy of you hypocrites, as it is written, “‘This people honors me with their lips, but their heart is far from me; in vain do they worship me, teaching as doctrines the commandments of men.’

Isaiah 29:13 English Standard Version

And the Lord said: “Because this people draw near with their mouth and honor me with their lips, while their hearts are far from me, and their fear of me is a commandment taught by men,

That is not a word for word quote but close enough to discover the connection.

The condition of their hearts is identified as the problem in Mark 7 but is expressed as fearing God in Isaiah as a tradition of man. That is not reverence for God which caused their hearts to be far from Him. In Mark 7 it is expressed as a vain attempt, meaning their tradition did not accomplish what God intended for man.

Traditions appear throughout the bible and God does not correct or nullify them if those traditions do not interfere with true worship. God lets the insignificant slide, something that I have had to learn how to do.