When I was a young lad, I learned this verse as a memory verse in the King James Version (KJV) of the Bible. If you look up the verse in the New American Standard Bible (NASB) today, the word “right” has been changed to “steadfast.” Which one is correct? Both are considered good translations of the Bible.
Quick answer – they are both correct. Both are possible meanings of the Hebrew word in context. Let’s ask the Lord to continually to change our hearts to His, to grant us His heart and His spirit within us. Our hearts are human and corrupt. If we lean on our own understanding, we will fall. We must lean on Him and His word and ask Him to renew us day by day.
A word on translations: If you look in Strong’s Dictionary of Hebrew words, the number assigned to this word is 3559. Strong’s is linked to the Authorized English Version of the Bible. Hebrew word 3559 is spelled kuwn (pronounced “koon”). The primitive root means to be erect. The word can have many meanings depending on sentence structure and application, but for Psalm 51:10 KJV translators believe the word to be “right.” NASB translators chose the word “steadfast.”
Use caution when studying the Bible. Know the power of the translation and why you use it.
As far as which translation is best to use for accuracy, read the article written by Matt Slick at http://carm.org/which-bible-version-is-best. This gives you an idea of choosing between a literal translation or a “meaning-leaning” translation that tries to smooth out the language differences. The most literal translations according to Slick are the New American Standard Bible (NASB), the King James Version (KJV) and the English Standard Version (ESV). These versions try to stay as close to the literal meaning of the Hebrew and Greek words and are the current best versions for standing on God’s word for the essence of what was written in the past.
As a side note, there are many different Bible search engines (free) that you can use to read a verse in different translation versions. When I’m looking for a verse in the Bible on the internet, I use BibleGateway at: http://www.biblegateway.com.