First, believers will be taken immediately into the presence of Christ in heaven. Christ is in heaven now (Acts 1:2; 3:21; 1 Thes 1:10; 4:16; 2 Thes 1:7), and believers will go to be with Him. Jesus said to the thief on the cross, "Truly I say to you, today you shall be with me in Paradise" (Luke 23:43). Not until the Rapture will believers receive a gloriied body. Meanwhile, the perishable body only is in the grave.
Now I say this, brethren, that flesh and blood cannot inherit the kingdom of God; nor does the perishable inherit the imperishable. Behold, I tell you a mystery; we will not all sleep, but we will all be changed, in a moment, in the twinkling of an eye, at the last trumpet; for the trumpet will sound, and the dead will be raised imperishable, and we will be changed. For this perishable must put on the imperishable, and this mortal must put on immortality. (1 Cor 15:50-53)
On two different occasions Paul spoke of death as ushering us into the presence of Christ: But I am hard-pressed from both directions, having the desire to depart and be with Christ, for that is very much better; yet to remain on in the flesh is more necessary for your sake. (Philippians 1:23-24)
Therefore, being always of good courage, and knowing that while we are at home in the body we are absent from the Lord--for we walk by faith, not by sight--we are of good courage, I say, and prefer rather to be absent from the body and to be at home with the Lord. Therefore we also have as our ambition, whether at home or absent, to be pleasing to Him. (2 Corinthians 5:6-9)
For to me, to live is Christ and to die is gain. But if I am to live on in the flesh, this will mean fruitful labor for me; and I do not know which to choose. (Phil 1:21-22)