it's certainly the case that the early disciples who saw Christ's Ascension weren't meant to believe that His Second Advent might be imminent, as so many insist that all Christians must believe now. Some even insist - often through a poor understanding of English - that they believe that His Second Advent is imminent, when what they actually mean is that they believe that it might be imminent.
Nothing could be more ridiculous than that they had just seen Jesus leave this Earth, and yet they were expected to believe that His Second Advent might be imminent.
The Apostle Paul disabuses some early Christians that had got this erroneous notion and had also gone further in their erroneousness.
Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto him.That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand. Let no man deceive you by any means: for, except there come a falling away first, and that man of sin be revealed, the son of perdition;(II Thess 2:1-3)
Looking for and hasting after Christ's Second Advent is a moral state of the believer, and involves being born again and not being in a state of backsliding:
But ye, brethren, are not in darkness, that that day should overtake you as a thief. Ye are all the children of light, and the children of the day: we are not of the night, nor of darkness. Therefore let us not sleep, as do others; but let us watch and be sober. For they that sleep sleep in the night; and they that be drunken are drunken in the night. But let us, who are of the day, be sober, putting on the breastplate of faith and love; and for an helmet, the hope of salvation.(I Thess 5:4-8)
It does not involve being on tenterhooks with the erroneous notion - not that Christ's coming is imminent, if we know that it's imminent then we are saying that we know it is going to happen shortly - but that the end of the World might be imminent.
There are many indications in Scripture that the Second Advent - as the Parousia at the Eschaton - is not imminent, and that that is not incompatible with saying that we don't know when the Second Advent and Eschaton are going to happen.