Netzach ("victory" or "eternity") is one of the "sefirot, the fourth of the emotional attributes.
Netzach is the will to be victorious, the determination to overcome all obstacles.
Hod is the power to persevere even when faced with obstacles that seem insurmountable.
It is the power of acknowledgment: admitting that God is right even when one does not understand, recognizing that He is the one true reality and giving praise and glory to Him.
Although netzach and hod are, in a sense, opposites, they work together like two aspects of a single entity.
Their common purpose is to strengthen the intellectual and emotional "energy" of the middot and to channel it into tangible, practical results, despite any internal or external opposition.
The middot correspond to the primary emotions of love, fear, and mercy and the behavioral impulses of domination, acknowledgment, and bestowing influence.
One metaphor pictures netzach and hod as "a pair of millstones" working together to turn wheat into flour, an image that expresses their role in "processing" the spiritual energy of the higher attributes and making it available in a way that will benefit others.
–Rabbi Adin Steinsaltz
From Opening the Tanya by Rabbi Adin Steinsaltz