Passage
For this reason a man shall leave his father and mother,
For this reason a man shall leave his father and mother,
Mark 10:5 But Jesus said to them, “Because of your hardness of heart he wrote for you this commandment.
Mark 10:6 But from the beginning of creation, God made them male and female.
Mark 10:7 For this reason a man shall leave his father and mother,
Mark 10:8 and the two shall become one flesh; so they are no longer two, but one flesh.
Mark 10:9 What therefore God has joined together, let no man separate.”
The verse centers on "reason", "shall", "leave", "father", and "mother". It is saying that the verse draws attention to "reason" and "shall", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 6's "But from the beginning of creation God..." into verse 8's "and the two shall become one flesh...", so "reason" and "shall" belong inside that flow. In Mark context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "reason" and "shall" with trust shaped by these words, not by a vague optimism outside the passage.