Being overcome by fruits of his action, he enters a good or evil womb, so that his course is downward or upward, and he wanders around, overcome by the pairs of opposites.
KYV, MAITRI UPANISHAD 3.2
Just as spokes are affixed to the hub of a wheel, so are all things established in life, the Rig and Yajur and Sama Veda, Sacrifice, the nobility and also the priesthood.
ATHARVA VEDA, PRASNA U 2.6
According as one acts, according as one behaves, so does he become. The doer of good becomes good. The doer of evil becomes evil. One becomes virtuous by virtuous action, bad by bad action
SHUKLA YAJUR VEDA, BRIHADARANYAKA UPANISHAD 4.4.5
One should not be negligent of truth, virtue or welfare. One should not be negligent of prosperity. One should not be negligent of study and teaching.
KRISHNA YAJUR VEDA, TAITTIRIYA UPANISHAD 1.11.1
Stirring both worlds the Brahmachari moveth: in him the deities are all one-minded. He hath established firmly earth and heaven: he satisfies his Master with his Fervor.
ATHARVA VEDA 11.5.1