Matthew 13:20–21 describes all who enthusiastically receive the Word, yet never grow in the faith. Their faith has no roots (Ephesians 3:17; Colossians 2:7). They are fickle people (proskairos: only for a while). One could say that the rocky ground that the seed fell on does not let it take root, but only holds it briefly, or that if the Word disappears, that ground is no longer soil.
In Matthew 13:20–21, Jesus speaks of those who enthusiastically receive the Word, yet never start to grow in the faith. Their faith has no roots, no depth (see Ephesians 3:17; Colossians 2:7). They are people of the moment (proskairos—only for a while), as changeable as the weather and therefore a plaything of circumstances.1
One can describe it this way: the rocky ground that received the seed does not allow it to take root, but only holds it for a short time. One can also say: if the Word disappears, then the sown soil no longer exists—it was only there temporarily.2
20 As for what was sown on rocky ground, this is the one who hears the word and immediately receives it with joy,