Why was the cross depicted on the cloaks of members of various orders?

Why was the cross depicted on the cloaks of members of various orders? Why did the members of the order always wear knightly armor under the monastic cloak?

Knightly Orders emerged during the first crusades to the Holy Land. The medieval knights were soldiers of Christ. Protecting the Christian faith for them was not only a duty, but also an honor. Entering the monastic order, the knight took an oath and bound himself with a given vow in front of all members of the order. A cross was depicted on the cloaks of the knights so that everyone could see to which order it belongs and its goal is to protect the Christian faith. Under a cloak, the knight wore armor because only with a sword in hand could one stand up for faith in opposition to the Gentiles.