Hebrews 10:39

But we are not of those who draw back to perdition, but of faith to the saving of the soul.

Luke 17:31-32

In that day let not him that shall be on the house, and his furniture in the house, come down to take it away; and in like manner let not him in the field turn back for things which are behind;

Acts 15:38

but Paul thought not best to take with them one who deserted them at Pamphylia and did not go with them to the work.

2 Timothy 4:10

for Demas forsook me having loved the present life and went to Thessalonica, Cresces to Galatia, Titus to Dalmatia;

Treasury of Scripture Knowledge

Summary

Because they turned back from him, and would not consider any of his ways:

Bible References

Turned

Luke 17:31
In that day let not him that shall be on the house, and his furniture in the house, come down to take it away; and in like manner let not him in the field turn back for things which are behind;
Acts 15:38
but Paul thought not best to take with them one who deserted them at Pamphylia and did not go with them to the work.
2 Timothy 4:10
for Demas forsook me having loved the present life and went to Thessalonica, Cresces to Galatia, Titus to Dalmatia;
Hebrews 10:39
But we are not of those who draw back to perdition, but of faith to the saving of the soul.