Do not commit to anyone: It is the fool who always rushes to take sides. Do not commit to any side or cause but yourself. By maintaining your independence, you become the master of others – playing people against one another, making them pursue you.
Professional versus personal vignette is the dichotomy I would argue. You certainly must observe this law in professional circles to avoid career and reputation detriment. The opposite I believe must occur in the inner most personal circle. To not be the defender or champion of a spouse or person maintaining a similar position in your life would be detrimental to that, your closest relationship.