Does God know about all our actions and also whatever we talk?
Yes God knows even what you talk secretly. See the following Atharva Veda (AV) Mantra:
Dvau samnishadya yat mantrayete rAja tat veda varunah tritiyah ||
When you talk in secret, there is always the third observer, divine observer Varuna.
So, God is monitoring all our actions, even though we might think that we are doing those actions secretly.
The following three Manu Smriti verses make things even more clear.
8.84. ’The Soul itself is the witness of the Soul, and the Soul is the refuge of the Soul; despise not thy own Soul, the supreme witness of men.
8.85. ’The wicked, indeed, say in their hearts, "Nobody sees us;" but the gods distinctly see them and the male within their own breasts.
8.86. ’The sky, the earth, the waters, (the male in) the heart, the moon, the sun, the fire, Yama and the wind, the night, the two twilights, and justice know the conduct of all corporeal beings.’
So, yes Gods very well know what we are doing or talking although we might be thinking that we have done those actions "secretly".
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