Jamieson, Fausset and Brown on Isaiah 48:8

8. heardest not--repeated, as also "knewest not," from Is 48:7.

from that time--Omit "that." "Yea, from the first thine ear did not open itself," namely, to obey them [Rosenmuller]. "To open the ear" denotes obedient attention (Is 50:5); or, "was not opened" to receive them; that is, they were not declared by Me to thee previously, since, if thou hadst been informed of them, such is thy perversity, thou couldst not have been kept in check [Maurer]. In the former view, the sense of the words following is, "For I knew that, if I had not foretold the destruction of Babylon so plainly that there could be no perverting of it, thou wouldst have perversely ascribed it to idols, or something else than to Me" (Is 48:5). Thus they would have relapsed into idolatry, to cure them of which the Babylonian captivity was sent: so they had done (Ex 32:4). After the return, and ever since, they have utterly forsaken idols.

wast called--as thine appropriate appellation (Is 9:6).

from the womb--from the beginning of Israel's national existence (Is 44:2).