Of course. It is very important to address them in this way and to always treat your in-laws with all due respect. Addressing the words “Father” and “Mother” (and not Mr. or Mrs.) is a manifestation of love and respect for the parents of your husband or wife, who is now one body with you. And not just address them that way, but always show them respect and care in all things, as you show them to your parents. Here is how the Bible says that Moses behaved with his father-in-law when he came to visit him in the wilderness:
Then Moses went out to meet his father-in-law, and he bowed down and kissed him; and they asked each other of their welfare and went into the tent. (Exodus 18:7)( NASB)
But you will tell me that nowhere in the Bible is a commandment addressed to our in-laws. True, there is no such command, but the Bible teaches us to give honor to those who deserve it. The apostle Paul was not ashamed to call Rufus’ mother a “mother,” even though she was neither his mother nor his mother-in-law, but because she treated him like a mother. The apostle writes:
Greet Rufus, a choice man in the Lord, also his mother and mine. (Romans 16:13)( NASB)
The evangelist John, when recounting the crucifixion of Jesus, writes these words:
Therefore the soldiers did these things. But standing by the cross of Jesus were His mother, and His mother’s sister, Mary the wife of Clopas, and Mary Magdalene. When Jesus then saw His mother, and the disciple whom He loved standing nearby, He said to His mother, “Woman, behold, your son!” Then He said to the disciple, “Behold, your mother!” From that hour the disciple took her into his own household. (John 19:25-27)( NASB)
Jesus left the disciple whom he loved with the responsibility to care for his mother. So you, if you say “Mother” and “Father” to your in-laws (and just call them that), know that you have the responsibility to take care of them in the same way as you do with your parents, because you have entered into a marriage covenant with their child and you are not only one body with him, but you also have common responsibilities. God help you.
Translated by Ina Croitoru