What should a wife do to persuade her husband to grow a beard, when he refuses, and is he sinful for his refusal?

Shaving the beard is an act of disobedience and a contravention of the guidance of the Prophet, peace and blessings be upon him, and his command to let it grow. It is obligatory to advise those who shave it with wisdom and good admonition, and to persevere in inviting them to Allah, seeking reward from Him. It is recommended to strive in supplicating for them during times when prayers are answered.