According to the timeline of Hindu texts, based on (historical) dating:
The oldest scripture still extant is Rig Veda Samhita, whose composition is usually dated to roughly between 1800 – 1100 BCE. There is a debate on whether there is a mention of multiple rebirths in Rig Veda Samhita. If we consider the implicit mentioning, then Rig Veda is the first ...
There are two classes of devotees: Jivakotis and Isvarakotis. Here, koti means type or like;
Jivakotis are ordinary men (like Jiva) and
Isvarakotis are Divine men (like Isvara).
For Jivakotis, Moksha is a permanent state.
For Isvarakotis, Moksha is not a permanent state. Because,
He is a person commissioned by God to do good to the world; though liberated ...
Thanks to the eternal Srimad Bhagwad Gita which elaborates facts pretty simply(knowing such facts isn't any way possible as such in a lifetime):
As per the 'time of death' one can know what's the basic outcomes of the being:
यत्र काले त्वनावृत्तिमावृत्तिं चैव योगिन: |
प्रयाता यान्ति तं कालं वक्ष्यामि भरतर्षभ || 23||
अग्निर्ज्योतिरह: शुक्ल: षण्मासा उत्तरायणम् ...