Problem: Jesus said, “[The mustard seed] is smaller than all other seeds” (Mt. 13:32). However, scientifically, we know that the mustard seed is not the smallest seed. Did Jesus err in making this statement?
Solution: This can be resolved by considering the context. In the previous verse, Jesus says that “a man took and sowed in his field” (v.31). Thus Jesus was saying that the mustard seed is the smallest seed in the fields of Palestine. The scope of this statement was not the entire Earth, but rather, the agrarian setting of ancient Palestine. This would be similar to a car salesman saying, “This is the fastest car on the lot.” He isn’t saying that this is the fastest of all the cars on Earth. The context is the car lot—not all of planet Earth. Jesus used the concept of a mustard seed to refer to its small size (Mt. 17:20; Lk. 17:6), and rabbis frequently used the mustard seed as “proverbial in Jewish thinking as the smallest of all seeds.”
 Lane, W. L. (1974). The Gospel of Mark (p. 171). Grand Rapids, MI: Wm. B. Eerdmans Publishing Co.
“It is like a grain of mustard seed, which, when it is sown in the earth, is less than all the seeds that be in the earth: (Mark 4:31)