New Living Translation
for they still didn’t understand the significance of the miracle of the loaves. Their hearts were too hard to take it in.

American Standard Version
for they understood not concerning the loaves, but their heart was hardened.

Berean Study Bible
for they had not understood about the loaves, but their hearts had been hardened.

Douay-Rheims Bible
For they understood not concerning the loaves; for their heart was blinded.

English Revised Version
for they understood not concerning the loaves, but their heart was hardened.

King James Bible
For they considered not the miracle of the loaves: for their heart was hardened.

World English Bible
for they hadn't understood about the loaves, but their hearts were hardened.

Young's Literal Translation
for they understood not concerning the loaves, for their heart hath been hard.

Mark 6:52 Additional Translations ...