Jamieson, Fausset and Brown on Daniel 6:10

10. when Daniel knew ... writing ... signed--and that, therefore, the power of advising the king against it was taken from him.

went into his house--withdrawing from the God-dishonoring court.

windows ... open--not in vainglory, but that there might be no obstruction to his view of the direction in which Jerusalem, the earthly seat of Jehovah under the Old Testament, lay; and that the sight of heaven might draw his mind off from earthly thoughts. To Christ in the heavenly temple let us turn our eyes in prayer, from this land of our captivity (1Ki 8:44, 48; 2Ch 6:29, 34, 38; Psa 5:7).

chamber--the upper room, where prayer was generally offered by the Jews (Ac 1:13). Not on the housetop (Ac 10:9), where he would be conspicuous.

upon his knees--Humble attitudes in prayer become humble suppliants.

three times a day--(Psa 55:17). The third, sixth, and ninth hour; our nine, twelve, and three o'clock (Ac 2:15; 10:9; 3:1; 10:30; compare Da 9:21).

as ... aforetime--not from contempt of the king's command.