Whoever Allah has blessed with a righteous woman – He has aided him in half of his deen [religion, faith]; and let him fear Allah in the remaining half. (Hadith of Anas, recorded in Al-jami’ Al-saghir)
This is because the greatest piercing trial in deen is the desire of the stomach and the desire of the crotch; with a righteous woman, chastity against adultery is ensured, and this is the first half. The second half remains, this being the desire of the stomach, and He enjoins piety in this so that one’s faith may be made whole and he may remain upright.