Philippians 2

3 Let nothing be done through selfish ambition or conceit, but in lowliness of mind let each esteem others better than himself.

You can predict which marriages will fail by one single marker in the conversation: contempt. If the couple commonly speak down to one another, even if it is light-hearted, then the relationship may well falter. Submitting to one another, and considering one another to be more valuable is glue to any relationship.
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