For an Islamic marriage to be valid, the three principles of marriage that must be adhered to are:
a. There must be a marriage guardian known as the Waliy who represents the bride in the marriage negotiations. The Waliy cannot be a non-muslim.
b. There must be legality of marriage between the couple. The woman must be not permanently prohibited to the man under Nasab which is consanguinity, Rada which is fosterage and Musaharah which is affinity. Any marriage between couples under the prohibited degrees of consanguinity, affinity or fosterage is void. Jinadu Adigun v. Awawu Ajoke KWS/SCA/CV/IL/30/94.
c. There must be formal statements of offer and acceptance. This is known as Seegah. The Waliy comes into play here. He makes the offer giving the hand of the bride in marriage and the suitor makes a formal declaration of acceptance. The seegah must be done verbally for its validity.