He said that he was going to stick with the traditions established by his grandfather.

stick 的本义是"棍棒"，作为动词时表示"粘住、固定"，引申为"坚持"的意思。 with 是介词，表示"和...一起"，在这里与 stick 搭配使用。 stick with 是一个短语动词，意思是"坚持、不放弃"，指持续做某事或保持某种状态不改变。