While Jesus Christ was with his disciples he said that
even he did not know the day or hour of his return:

"But of that day and that hour knoweth no man, no, not
the angels which are in heaven, neither the Son, but
the Father." Mark 13:32

But the Bible tells us later on that the Father did
reveal all of it to Jesus Christ:

"The Revelation of Jesus Christ, which God gave unto
him, to shew unto his servants things which must
shortly come to pass; and he sent and signified it by
his angel unto his servant John:" Revelation 1:1

Notice it is the revelation that God the Father gave
to God the Son regarding his return and all the future
things to take place.

Then Jesus Christ reveals it to John by an angel, who
writes Revelation for the rest of us to know what will
happen.

So its not that God never revealed the day, but rather
that he revealed it in his own timing.

So this verse (Revelation 1:1) supercedes Acts 1:8
where it says, "And he said unto them, It is not for
you to know the times or the seasons, which the Father
hath put in his own power."

The disciples were to wait only for the next events,
Pentacost and the spread of the Gospel around the
world, and were not get ahead of themselves worrying
about the second coming. But after Acts 1:9 is is
fulfilled, then the next stage is revealed for the
saints to know, as it tells us in Revelation 1:1.

Paul writes, "But ye, brethren, are not in darkness,
that that day should overtake you as a thief." 1
Thessalonians 5:4

The Bible says, "Surely the Lord GOD will do nothing,
but he revealeth his secret unto his servants the
prophets." Amos 3:7

And Daniel wrote, "He revealeth the deep and secret
things: he knoweth what is in the darkness, and the
light dwelleth with him. I thank thee, and praise
thee, O thou God of my fathers, who hast given me
wisdom and might, and hast made known unto me now what
we desired of thee: for thou hast now made known unto
us the king's matter." Daniel 2:22-23
 

The Lord's return is very near, as he has revealed to
us in scripture and confirmed by the witness of the
Holy Ghost in us his servants.

Let us remember that it is not a time to be ambitious
for the things of the world, because the current order
of things will soon be removed.

Ambitious Baruch was dismayed about Jeremiah's
prophesy that Jerusalem would be destroyed soon
because it was going to ruin his "career plans" - but
the word from the Lord to him was to forget about all
that - be glad he would escape:

"Thus saith the LORD, the God of Israel, unto thee, O
Baruch: Thou didst say, Woe is me now! for the LORD
hath added grief to my sorrow; I fainted in my
sighing, and I find no rest.

Thus shalt thou say unto him, The LORD saith thus;
Behold, that which I have built will I break down, and
that which I have planted I will pluck up, even this
whole land.

And seekest thou great things for thyself? seek them
not: for, behold, I will bring evil upon all flesh,
saith the LORD: but thy life will I give unto thee for
a prey in all places whither thou goest."

Jeremiah 45:2-5
 

Maranatha!