Yoga Rahasya Chapter Two verse 45

sthitikramānurodhena gṛhiṇām yogasādhane |
prāṇāyāmo mukhyatama iti me matamuttamam ||

In the Sthiti Krama the most important Yoga Sādhana
for the householder, according to me, is Prāṇāyāma.

sthiti - staying or remaining or being in any state or condition; maintenance of life;krama - sequence; order; series; regular arrangement; succession; progressing step by step; in regular course; gradually, by degreesgṛhastha - standing in the home; living or staying in any one's house; householderyoga - the act of yokingsādhana - means to accomplish; leading straight to a goal; guiding well; furtheringprāṇāyāma - extending the breathiti - thus; in this mannermata - a thought, idea, opinion, view, sentiment