That may have been applicable before the crucifixion, resurrection, ascension, and exaltation of Christ. But since He Himself announced that ALL power and authority in Heaven and on earth had been given to Him (Mt 28:18) it follows that at this time the Son of God knows precisely when He will return, and all other events preceding and succeeding His return.
Since we are definitely NOT in the Tribulation or Great Tribulation, but in the period known as the Great Apostasy, those events are still in the future. It is only when the heavenly bodies as well as the earth are seriously shaken out of their places that people may expect the Second Coming of Christ. So in that sense, there will be a time when the inhabitants of the earth will be in great fear while expect Christ to come with power and great glory.
We should take note of the following passages:
Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken: And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of Man coming in the clouds of Heaven with power and great glory. (Mt 24:29,30)
REVELATION 6: THE SECOND COMING OF CHRIST
12 And I beheld when he had opened the sixth seal, and, lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood; 13 And the stars of heaven fell unto the earth, even as a fig tree casteth her untimely figs, when she is shaken of a mighty wind. 14 And the heaven departed as a scroll when it is rolled together; and every mountain and island were moved out of their places... 16 And said to the mountains and rocks, Fall on us, and hide us from the face of him that sitteth on the throne, and from the wrath of the Lamb: 17 For the great day of his wrath is come; and who shall be able to stand?