All praise is due to Allah, and may exaltation and safety be granted to Muhammad, his family, his companions, and those who aid them. To proceed:
One of our Salaf, Fudayl Ibn ‘Iyaad [d. 187 A.H.], may Allah have mercy on him, said:
“Whoever marries his beloved daughter to an innovator has cut off the ties of relationship with her.” (1)
Shaykh Ahmad an-Najmee [d. 1429 A.H.], may Allah have mercy on him, said about this passage:
In this statement is a prohibition of marring your beloved daughter to an innovator and being loose towards them, all of that is prohibited, and it is a stern warning about mixing with and befriending innovators as we have mentioned before. (2)
Shaykh Saalih al-Fawzaan, may Allah protect him, said about this passage:
It is obligatory upon those who have the responsibility of guardianship over a daughter or a sister, and for those who are responsible for approving a marriage contract that they choose someone who is a suitable and righteous spouse.
The Messenger, may Allah exalt his mention and grant him safety, said: “If someone comes to you whose religion and trustworthiness pleases you, marry him. If you do not do this, there will be turmoil (fitnah) on Earth and great corruption.”
So, if you do not thoroughly investigate for the women whom you are in charge of, in order to find someone whose religion and trustworthiness is pleasing, there will be great corruption from the angle that you will marry her to someone from the people of hypocrisy, or to someone from the people of innovation, and she will be lead astray with him, and you will be the cause of that. (3)
Shaykh Rabee Ibn Haadee al-Madkhalee, may Allah protect him, said about this passage:
It is not befitting for a Salafee Sunnee to marry off a woman whose affairs he is in charge of to a companion of innovation. The Messenger, may Allah exalt his mention and grant him safety, said: “All of you are care-takers, and all of you are responsible for your flock.”
So, the daughter of a man, his sister or whom he is responsible for are from his flock, and he is responsible for them. The Messenger, may Allah exalt his mention and grant him safety, warned about keeping bad company. So, how can this guardian marry her off to an innovator who will have authority, the final word and a long life of control and authority over her?!
There are other aspects that a guardian takes into consideration such as financial and physical abilities, lineage, personal preferences that the woman may desire, etc. However, this article is meant to highlight the importance of choosing a man with sound religion.
May Allah, The All-Able, bless the women of this nation with husbands from the People of the Sunnah!