Mark 4:16

And these in like manner are those that are sown upon the rocky places, who, when they have heard the word, straightway receive it with joy.

In like manner ... indicates that the analogy of the seed as the word is to be continued and that the various soils are classes of hearers.

Receive it with joy ... The joyful reception of the great promises of the gospel by souls which are essentially "shallow" and superficial in their thinking is a well known phenomenon. The easier the convert is to convince, the greater the likelihood of his falling away. This fact derives from the truth that the gospel is not a matter of merely receiving great promises; but it is also a matter of denying self, acknowledging Jesus as Lord, and of deliberately choosing a way of life that is opposed to much that is found in every society. The joyful, fast, and ready receivers of the word are here compared to shallow soil on a ledge of stone which germinates seed quickly but cannot sustain their growth.