A Faustian Pact is a link and bargain between a human and Satan or a lesser demon. The latter offers specific services and fulfills the individual human's wish or desire in compensation of consuming the said human's soul after the contract is completed.
The demon might consume the human's soul, after fufilling the wishes of the human, at even the cost of their life.
To fulfill something tantalising and difficult to accomplish, such as a satisfying revenge, a human is required to give up their soul as payment.
It is also understood that some individuals make this type of pact just as a sign of recognising the Devil as their master, in exchange for nothing.
The pact can be oral or written. An oral pact is made by means of invocations, conjurations, or rituals to attract the demon. Once the conjurer thinks the demon is present, he/she asks for the wanted favour and offers his/her soul in exchange, and no evidence is left of the pact; but according to some witch trials and inquisitions that were performed, even the oral pact left evidence, namely the diabolical mark, an indelible mark where the marked person had been touched by the Devil to seal the pact. The mark could be used as a proof to determine that the pact was made. It was also believed that on the spot where the mark was left, the marked person could feel no pain. A written pact consists in the same forms of attracting the demon, but includes a written act, usually signed with the conjurer's blood (although sometimes was also alleged that the whole pact had to be written with blood). Forms of these include contracts or simply signing your name into Satan's Red Book. The Malleus Maleficarum discusses several alleged instances of pacts with the Devil, especially concerning women. It was considered that all witches and warlocks had made a pact with a demon, especially with Satan.
According to demonology, there is a specific month, day of the week, and hour to call each demon, so the invocation for a pact has to be done at the right time. Also, as each demon has a specific function, a certain demon is invoked depending on what the conjurer is going to request.
In the narrative of the Synoptic Gospels, Jesus is offered a series of bargains by the Devil, in which He is promised worldly riches and glory in exchange for serving the Devil rather than God. After Jesus rejects the Devil's temptation, He embarks upon his journey as the Messiah.