Out of the mouth of babes

A friend asked me about these two verses, and I don’t believe that we’ve looked at them before:

Out of the mouth of babies and infants, you have established strength because of your foes (Psalm 8:2a, ESV)

And Jesus said to them, “Yes; have you never read, “‘Out of the mouth of infants and nursing babies you have prepared praise’?” (Matthew 21:16b, ESV)

Now as your Bible’s footnotes probably tell you, this is another example where the New Testament has followed the Greek Septuagint rather than the Hebrew text.

Why though did the authors of the Septuagint translate this verse as they did? I don’t know, but maybe you do, and can help explain these strange verses.

It is also worth noting that our many English translations vary quite widely on these verses. Which do you think conveys the meaning best?