What is the difference between a Contract, an Oath, a Blood Oath and a Covenant?

CONTRACT:

A Contract is a temporary exchange.  You and/or the other accomplish something in an agreed upon time frame and you can move on. In everyday life most of us enter into many types of contracts:  a warranty on some product or car is a type of contract.    

In magic, a Contract is a formal magical agreement that outlines terms, exchanges, and expectations between you and another being or another magical practitioner. 

--------Contracts are transactional.  They can be permanent or temporary.

OATH:

An Oath is a sacred vow made with your spirit, guides, or deities, binding you through intention, honor, and personal power. 

--------Oaths are rooted in devotion and loyalty.  They tend to always be permanent.

BLOOD OATH:

A Blood Oath is one expression or type of Oath that is sealed in the blood of the one making the Oath.  It is both a symbol and a physical bond that make the Oath stronger. 

Many Satanists, but not all, have taken a Blood Oath to Satan.  The Blood Oath may – or might not – be required in the various different Satanic traditions.  Some insist on it.  Others have it as an option for those who feel ready for it.  Others do not use it at all. 

COVENANT:

A Covenant is a dedication of loyalty to a Coven of Witches.  The general practice is to start new dedicants off with a Contract – give them and the Coven members a chance to see if the new one is a good fit.  Once there is a mutual agreement that the new member is a good fit within the Coven, then very often the formal Covenant Oath is made. 

--------Covenants are formal agreements usually with an existing, organized group of Witches.  They may be temporary or permanent.  Usually moving from temporary to permanent over time.