Is it obligatory to slaughter the sheep vowed for the upcoming wedding anniversary immediately, or is it permissible to postpone it? And does postponement entail any consequences? Is it permissible to divide it into portions? And is it permissible to eat from it?

Fulfilling a vow (nadhr) is only obligatory if it is an act of worship (qurbah) that is not already compulsory. The mere act of slaughtering is not an act of worship unless its intention is to give its meat as charity. If the intention of drawing near to Allah was not present, or if it was not expressed verbally, then the vow is not valid because it falls under the category of vowing a permissible act (nadhr al-mubah). However, if the intention of drawing near to Allah was present, or if the word "charity" was mentioned, then it refers to slaughtering the animal and distributing its meat to the poor. If fulfilling it becomes obligatory, there is no harm in delaying a part of it until the following year, provided that no specific year was designated for the vow. No consequence arises from the delay because fulfillment is not an act that requires immediate performance. It is important to note that celebrating wedding anniversaries or birthdays is not part of Islam.