Is it permissible for a Muslim to sanctify a specific day of the week, what is the ruling on sanctifying Sunday for Muslims, and what is the ruling on using the phrase "Sunday is a happy day"?

It is disliked by the people of knowledge to sanctify a specific day of the week; therefore, it is disliked to refrain from work on Friday out of veneration for it. It is forbidden for Muslims to sanctify Sunday, as it constitutes imitation of Christians, and the Prophet, peace and blessings be upon him, forbade that by saying: "Whoever imitates a people is one of them," and "He is not of us who imitates others." Sunday is one of the holidays of the disbelievers, and it is forbidden to participate with them in it. It is not permissible to use anything upon which the phrase "Sunday is a happy day" is written if it is visible; rather, the phrase must be removed or covered.