What shall I do? Wicked men are driven to perplexity in their deliberations, because they do not know how any thing is to be lawfully used; [1] and, next, because they are intoxicated with a foolish confidence which makes them forget themselves. Thus we find that this rich man lengthens out his expectation of life in proportion to his large income, and drives far away from him the remembrance of death. And yet this pride is accompanied by distrust; for those men, when they have had their fill, are still agitated by insatiable desire, like this rich man, who enlarges his barns, as if his belly, which had been filled with his former barns, had not got enough. At the same time, Christ does not expressly condemn this man for acting the part of a careful householder in storing up his produce, but because his ravenous desire, like a deep whirlpool, swallows up and devours many barns; from which it follows that he does not comprehend the proper use of an abundant produce.

Footnotes

1 - "Pource qu'ils ne scavent point quel est le droit et legitime usage des creatures de Dieu;" -- "because they know not what is the proper and lawful use of the creatures of God."

He thought within himself - He reasoned or inquired. He was anxious and perplexed. Riches increase thought and perplexity. Indeed, this is almost their only effect - to engross the thoughts and steal the heart away from better things, in order to take care of the useless wealth.
No room - Everything was full.
To bestow - To place, to hoard, to collect.
My fruits - Our word "fruits" is not applied to "grain;" but the Greek word is applied to all the produce of the earth - not only "fruit," but also grain. This is likewise the old meaning of the English word, especially in the plural number.

He thought within himself - Began to be puzzled in consequence of the increase of his goods. Riches, though ever so well acquired, produce nothing but vexation and embarrassment.

And he (f) thought within himself, saying, What shall I do, because I have no room where to bestow my fruits?
(f) Reckoned with himself, which is the characteristic of covetous surly men who spend their life in those trifles.

And, he thought within himself,.... And foolish thoughts they were; he did not think of God, or that there was one, and much less that he was the author, of all his outward prosperity and plenty; and was still further off of thinking of returning thanks to God for it: or of asking counsel of him, what he should do with it; but he consults himself only, and thought only within, and for himself; and not at all of his poor neighbours, or for the good of others; nor did he think even of his own soul, but altogether about his worldly substance:
saying, what shall I do? he does not say what shall I do for God? for his interest service, and glory? for the poor, the hungry, and thirsty, and naked? or for my own soul, that that may be eternally saved? but what shall I do with my goods?
because I have no room where to bestow my fruits: he had gathered in his harvest, and filled his barns as full as they could hold, so that they had no room for more; and yet had still an abundance to lay up, and about which he was anxiously concerned; not thinking of the empty bellies, barns, and houses of the poor, where he might have stowed much.

What shall I do? - The very language of want! Do? Why, lay up treasure in heaven.