Adam Clarke on Matthew 15:8

Their heart is far from me - The true worship of God consists in the union of the heart to him - where this exists not, a particle of the spirit of devotion cannot be found.

This people draweth nigh unto me with their mouth - This clause, which is taken from Isa 29:13, is omitted by several excellent MSS., and by several versions and fathers. Erasmus, Mill, Drusius, and Bengel, approve of the omission, and Griesbach has left it out of the text; but as I find it in the prophet, the place from which it is quoted, I dare not omit it, howsoever respectable the above authorities may appear.