Now by asking, He means prayer, but by seeking, zeal and anxiety, as He adds, Seek, and ye shall find. For those things which are sought require great care. And this is particularly the case with God. For there are many things which block up our senses. As then we search for lost gold, so let us anxiously seek after God. He shews also, that though He does not forthwith open the gates, we must yet wait. Hence he adds, Knock, and it shall be opened unto you; for if you continue seeking, you shall surely receive. For this reason, and as the door shut makes you knock, therefore he did not at once consent that you might entreat.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom. 23. in Matt.