What does Matthew 6:7 mean?

Matthew 6:7 KJV
But when ye pray, use not vain repetitions, as the heathen [do]: for they think that they shall be heard for their much speaking.

Matthew 6:7 MKJV
But when you pray, do not babble vain words, as the nations. For they think that in their much speaking they shall be heard.

Matthew 6:7 NKJV
“And when you pray, do not use vain repetitions as the heathen [do]. For they think that they will be heard for their many words.

Matthew 6:7 KJV 2000
But when you pray, use not vain repetitions, as the heathen do: for they think that they shall be heard for their much speaking.

Interlinear KJV

But /de/ when ye pray, /proseuchomai/ use /battologeo/ not /me/ vain repetitions, /battologeo/ as /hosper/ the heathen /ethnikos/ do: for /gar/ they think /dokeo/ that /hoti/ they shall be heard /eisakouo/ for /en/ their /autos/ much speaking. /polulogia/

Albert Barnes’ Commentary

Verse 7. Use not vain repetitions. The original word here is supposed to be derived from the name of a Greek poet, who made long and weary verses, declaring, by many forms and endless repetitions, the same sentiment. Hence it means to repeat a thing often, to say the same thing in different words, or to repeat the same words, as though God did not hear at first. An example of this we have in 1 Ki 18:26: “They Called on Baal from morning until noon, saying, O Baal, hear us;”*

The heathen do. The original word is one commonly translated Gentile. The world was divided into two parts, the Jews and the Gentiles; that is, in the original, the “nations,” the nations destitute of the true religion. Christ does not fix the length of our prayers. He says that they should not repeat the same thing, as though God did not hear. And it is not improbable that he intended to condemn the practice of long prayers. His own supplications were remarkably short.

{q} “as the heathens do” Ec 5:2 {*} The following is a specimen of the vain repetitions of the Romans.

“Pious Antonine, the Gods preserve thee. Gentle Antonine, the Gods preserve thee. Gentle Antonine, the Gods preserve thee.”