Mark 10:20
And he answered and said unto him, Master, all these have I observed from my youth.
Cross-references
Matthew 19:20
Parallel
Matthew 19:20 is the parallel account, adding the ruler's question 'what do I still lack?' that leads into Jesus' response.
Philippians 3:6
Related theme
Philippians 3:6 recounts Paul's former blamelessness under the law, directly paralleling the ruler's confidence in his own obedience.
Luke 18:21
Parallel
Luke 18:21 records the exact same statement from the ruler, confirming the synoptic parallel of this story.