Luke 2:50
And they understood not the saying which he spake unto them.
Cross-reference
Luke 9:45
Parallel
Luke 9:45 describes the disciples' failure to understand Jesus' words—a repeated theme of incomprehension.
Luke 18:34
Parallel
Luke 18:34 again records disciples not understanding Jesus—continuing the Lukan theme of hidden understanding.
Mark 9:32
Parallel
In Mark 9:32, the same phrase 'they did not understand the saying' describes the disciples' incomprehension of Jesus' death prediction — mirroring the parents' confusion here.