In the gospels Jesus preaches "repent because the kingdom of God is imminent". He said it would arrive before the current generation died (IE: about 40 years). Not all of his hearers would die before the arrival. The arrival would be public with the Son of Man appearing in the sky for all to see and descending as he had "taken off".
However, if the people failed to repent and refused their king, the kingdom would not come:
KJV Mat 21:33 Hear another parable: There was a certain householder,
which planted a vineyard, and hedged it round about, and digged a
winepress in it, and built a tower, and let it out to husbandmen, and
went into a far country: Mat 21:34 And when the time of the fruit
drew near, he sent his servants to the husbandmen, that they might
receive the fruits of it. Mat 21:35 And the husbandmen took his
servants, and beat one, and killed another, and stoned another. Mat
21:36 Again, he sent other servants more than the first: and they did
unto them likewise. Mat 21:37 But last of all he sent unto them his
son, saying, They will reverence my son. Mat 21:38 But when the
husbandmen saw the son, they said among themselves, This is the heir;
come, let us kill him, and let us seize on his inheritance. Mat
21:39 And they caught him, and cast him out of the vineyard, and slew
him. Mat 21:40 When the lord therefore of the vineyard cometh, what
will he do unto those husbandmen? Mat 21:41 They say unto him, He
will miserably destroy those wicked men, and will let out his vineyard
unto other husbandmen, which shall render him the fruits in their
seasons. Mat 21:42 Jesus saith unto them, Did ye never read in the
scriptures, The stone which the builders rejected, the same is become
the head of the corner: this is the Lord's doing, and it is marvellous
in our eyes? Mat 21:43 Therefore say I unto you, The kingdom of God
shall be taken from you, and given to a nation bringing forth the
fruits thereof. Mat 21:44 And whosoever shall fall on this stone
shall be broken: but on whomsoever it shall fall, it will grind him to
powder. Mat 21:45 And when the chief priests and Pharisees had heard
his parables, they perceived that he spake of them. Mat 21:46 But
when they sought to lay hands on him, they feared the multitude,
because they took him for a prophet.
In fact, Paul explained that because of the rejection of Jesus by the Jewish leaders precisely what Jesus warned came to pass:
Act_13:46 Then Paul and Barnabas waxed bold, and said, It was
necessary that the word of God should first have been spoken to you:
but seeing ye put it from you, and judge yourselves unworthy of
everlasting life, lo, we turn to the Gentiles.
Paul explains that Jesus did not ultimately come to be crowned but rather to be rejected:
KJV Rom 11:25 For I would not, brethren, that ye should be ignorant
of this mystery, lest ye should be wise in your own conceits; that
blindness in part is happened to Israel, until the fulness of the
Gentiles be come in.
And so the many promises of the arrival of the kingdom did not occur. Instead there was a horrific judgment in the for of the Roman destruction of the temple, Jerusalem and a large percentage of the Jews. The Israel-centric program was, for the moment, terminated.
What Jesus promises to the twelve in John 14 was related to the arrival of the kingdom which, as we see played out, was not to come about at that time. Instead the "Church age" was ushered in among the gentiles. The realization of the kingdom promises have been deferred until a time in the distant future.
So what did Jesus promise? He promised that the new Jerusalem above, where God lives would descend to the middle east and make his abode with his people in the promised land. This is also what John promised in the latter part of the Revelation.
KJV Joh 14:1 Let not your heart be troubled: ye believe in God,
believe also in me. Joh 14:2 In my Father's house [the Jerusalem
above] are many mansions [safe accommodations]: if it were not so, I
would have told you. I go to prepare a place for you. Joh 14:3 And
if I go and prepare a place for you, I will come again, and receive
you unto myself; that where I am, there ye may be also.
His promise was the arrival of the city which Abraham also anticipated:
KJV Heb 11:8 By faith Abraham, when he was called to go out into a
place which he should after receive for an inheritance, obeyed; and he
went out, not knowing whither he went. Heb 11:9 By faith he
sojourned in the land of promise, as in a strange country, dwelling in
tabernacles with Isaac and Jacob, the heirs with him of the same
promise: Heb 11:10 For he looked for a city which hath foundations,
whose builder and maker is God.
Though the arrival of the city of God did not occur on schedule it will still occur, when the fullness of the gentiles has come in. Then Jesus will be king of Israel forever:
KJV 1Ch_22:10 He shall build an house for my name; and he shall be my
son, and I will be his father; and I will establish the throne of his
kingdom over Israel for ever.
God himself will be the King over the kings of the whole earth from his throne in Jerusalem, while Jesus will be one of the subject kings:
KJV 1Co 15:24 Then cometh the end, when he shall have delivered up
the kingdom to God, even the Father; when he shall have put down all
rule and all authority and power. 1Co 15:25 For he must reign, till
he hath put all enemies under his feet. 1Co 15:26 The last enemy
that shall be destroyed is death. 1Co 15:27 For he hath put all
things under his feet. But when he saith all things are put under him,
it is manifest that he is excepted, which did put all things under
him. 1Co 15:28 And when all things shall be subdued unto him, then
shall the Son also himself be subject unto him that put all things
under him, that God may be all in all.
Then will be fulfilled Jesus' promise:
KJV Joh 14:23 Jesus answered and said unto him, If a man love me, he
will keep my words: and my Father will love him, and we will come unto
him, and make our abode with him. Joh 14:24 He that loveth me not
keepeth not my sayings: and the word which ye hear is not mine, but
the Father's which sent me.
KJV Rev 21:2 And I John saw the holy city, new Jerusalem, coming down
from God out of heaven, prepared as a bride adorned for her husband.
Rev 21:3 And I heard a great voice out of heaven saying, Behold, the
tabernacle of God is with men, and he will dwell with them, and they
shall be his people, and God himself shall be with them, and be their
God. Rev 21:4 And God shall wipe away all tears from their eyes; and
there shall be no more death, neither sorrow, nor crying, neither
shall there be any more pain: for the former things are passed away.
Rev 21:5 And he that sat upon the throne said, Behold, I make all
things new. And he said unto me, Write: for these words are true and
faithful. Rev 21:6 And he said unto me, It is done. I am Alpha and
Omega, the beginning and the end. I will give unto him that is athirst
of the fountain of the water of life freely. Rev 21:7 He that
overcometh shall inherit all things; and I will be his God, and he
shall be my son.