Jesus was saying in Matthew 6:7 that we must not regard prayer as some kind of magical incantation, for that is how pagans pray. They recite certain phrases over and over again, with no understanding of what the words mean. In these contexts, prayers are used as mantras, with the hope that they will change the environment or the circumstances in which a person lives. New Age thinking is filled with this type of thing. Jesus did not commend such exercises as godly forms of prayer; rather, He linked the use of vain repetitions to paganism.
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