You can tell this is one of those passages the translators had a difficult time transposing into English. The difficulty is found in the last part of the second verse. The ESV says those judged by God as faithless missed God's promised blessing because "...they were not united by faith with those who listened." This is also the translation route taken by the NIV.
Take note of the "it" in that last phrase in verse 2 - "...because it was not united by faith in those who heard..." That "it" is the "word they heard." So what the New American Standard Version makes more vivid is the idea that the failure of Israel to enter the promised land was due to their not combining the message they heard - not hearing the word - mixed with faith. This is also the translation route taken by the KJV.
The ESV says the God's judgment on the people was due to their failure to fall in line with the faithful twosome of Joshua and Caleb in trusting God. These rebellious people didn't copy the faith of Joshua and Caleb when they heard the word from the Lord. And the price they paid was severe. They all died in the wilderness, being barred from the promised land.