John 15:4-6

be attach'd to me, and I shall be so to you. as the branch cannot bear fruit of it self, except it be attach'd to the vine: so neither can you, except you continue attach'd to me.

Acts 11:23

who upon his arrival there, was glad to see such effects of the divine grace, and exhorted them all to remain firmly attach'd to the christian profession:

Acts 27:31

upon this Paul said to the centurion and his men, "except the crew stay aboard, you can't be safe:"

Hebrews 3:14

for we were receiv'd into the communion of Christ, upon condition of inviolably maintaining the hope we had at the beginning even unto the end,

Hebrews 6:4-8

For it is impossible for those who were once enlightned, and have received the heavenly gifts, communicated by the holy spirit,

Hebrews 9:11-12

but Christ, the high priest of a better dispensation that was to come, having appeared, is enter'd into the holy of holys by a nobler and more perfect tabernacle, not the effect of human art, but of a higher nature;

Hebrews 9:15-17

and for this cause he is the mediator of the new testament, that, the transgressions that were unexpiated by the first testament, being expiated by his death, they who are called might receive the eternal inheritance, which was promised.

Hebrews 10:26-30

for if we wilfully apostatize, after having received the knowledge of the truth, it is as a sin for which there is no sacrifice appointed.

Hebrews 10:39

as for us, we are not such as desert to their own destruction; but such as persevere in the faith, to the saving of our souls.

Treasury of Scripture Knowledge

Summary

Because he should have remained in the city of his refuge until the death of the high priest: but after the death of the high priest the slayer shall return into the land of his possession.

After the death

Bible References

He should

John 15:4
be attach'd to me, and I shall be so to you. as the branch cannot bear fruit of it self, except it be attach'd to the vine: so neither can you, except you continue attach'd to me.
Acts 11:23
who upon his arrival there, was glad to see such effects of the divine grace, and exhorted them all to remain firmly attach'd to the christian profession:
Acts 27:31
upon this Paul said to the centurion and his men, "except the crew stay aboard, you can't be safe:"
Hebrews 3:14
for we were receiv'd into the communion of Christ, upon condition of inviolably maintaining the hope we had at the beginning even unto the end,
Hebrews 6:4
For it is impossible for those who were once enlightned, and have received the heavenly gifts, communicated by the holy spirit,
Hebrews 10:26
for if we wilfully apostatize, after having received the knowledge of the truth, it is as a sin for which there is no sacrifice appointed.

After the death

Hebrews 9:11
but Christ, the high priest of a better dispensation that was to come, having appeared, is enter'd into the holy of holys by a nobler and more perfect tabernacle, not the effect of human art, but of a higher nature;