The two true statements are:
1. Knights were hired by the vassal for the protection of the lord.
2. Feudal aid is where vassals would be ready to assist monetarily such as in giving ransom money in time of need.
The first statement is true because knights were often hired by vassals to protect the lord in the feudal system.
The second statement is true because "feudal aid" referred to the vassals being prepared to provide financial assistance, such as giving ransom money, in times of need.