“Be not ye therefore like unto them: for your Father knoweth what things ye have need of, before ye ask him.”
Matthew 6:8 — Greek Interlinear
Church Fathers on Matthew 6:8
As the hypocrites use to set themselves so as to be seen in their prayers, whose reward is to be acceptable to men; so the Ethnici (that is, the Gentiles) use to think that they shall be heard for their much speaking; therefore He adds, 'When ye pray, do not ye use many words.'
Hereby He dissuades from empty speaking in prayer; as, for example, when we ask of God things improper, as dominions, fame, overcoming of our enemies, or abundance of wealth. He commands then that our prayers should not be long; long, that is, not in time, but in multitude of words. For it is right that those who ask should persevere in their asking; 'being instant in prayer,' as the Apostle instructs; but does not thereby enjoin us to compose a prayer of ten thousand verses,…
What He condemns is many words in praying that come of want of faith; 'as the Gentiles do.' For a multitude of words were needful for the Gentiles, seeing the daemons could not know for what they petitioned, until instructed by them; they think they shall be heard for their much speaking.