Wikipedia
Oil of catechumens
Oil of the Catechumens is the oil used in some traditional Christian churches during baptism; it is believed to strengthen the one being baptized to turn away from evil, temptation and sin.
The catechumen, the person prepared for baptism, is also anointed as a symbol of being the heir of the Kingdom of God, as kings and queens were anointed at coronations, and empowered for their Christian life as prophets were anointed for their ministry.
Oil of Catechumens is intended to help strengthen the person about to be baptized, and prepare them for the struggle ( ascesis) of the Christian life, the way a wrestler in ancient Greece and Rome was anointed before a wrestling match.