So if the dead are already with Jesus where are the dead in Christ rising from?
Those who died in faith in the Old Testament are to be raised at the second coming of Christ.
Daniel 12:2 And many of them that sleep in the dust of the earth
shall awake, some to everlasting life, and some to shame and
everlasting contempt.
Hebrews 11:40 God having provided some better thing for us, that they
without us should not be made perfect.
Revelation 20:6 Blessed and holy is he that hath part in the first
resurrection: on such the second death hath no power, but they shall
be priests of God and of Christ, and shall reign with him a thousand
years.
Those who become Christians after Christ get their new life right away.
John 5:24 Verily, verily, I say unto you, He that heareth my word,
and believeth on him that sent me, hath everlasting life, and shall
not come into condemnation; but is passed from death unto life.
Because Christians have this new life in Christ while we are still alive, when the body dies, it remains here on earth, but the soul is with Jesus.
2 Corinthians 5:8 We are confident, I say, and willing rather to be
absent from the body, and to be present with the Lord.
This is how when Jesus returns for the rapture and brings with him the souls of dead Christians so that they are reunited with their resurrection bodies and we who are alive will be joined with them in bodies that are changed rather than resurrected.
1 Thessalonians 4:14-17 For if we believe that Jesus died and rose
again, even so them also which sleep in Jesus will God bring with him.
For this we say unto you by the word of the Lord, that we which are
alive and remain unto the coming of the Lord shall not prevent them
which are asleep. For the Lord himself shall descend from heaven
with a shout, with the voice of the archangel, and with the trump of
God: and the dead in Christ shall rise first: Then we which are
alive and remain shall be caught up together with them in the clouds,
to meet the Lord in the air: and so shall we ever be with the Lord.
1 Corinthians 15:51-52 Behold, I shew you a mystery; We shall not all
sleep, but we shall all be changed, In a moment, in the twinkling of
an eye, at the last trump: for the trumpet shall sound, and the dead
shall be raised incorruptible, and we shall be changed.