What was obligatory for every knight during the era of the Crusades?

The crusades in the Middle Ages were very popular, and the younger sons of the knights, who did not inherit anything from their father, had no opportunity to exist, went on holy campaigns against the Gentiles, namely the Muslims, who captured the holy city of Jerusalem for Christians.
Obligatory for the knight was not only the presence of equipment and a war horse, but also a canvas with an image of a cross, given to a soldier by a priest. Hence the name CROSS campaign and CRUSADERS. Also, the priest sprinkled holy water on the knight’s clothes.