Charles Ellicott Commentary 1 Samuel 2:3

"Talk no more so exceeding proudly; Let not arrogancy come out of your mouth; For Jehovah is a God of knowledge, And by him actions are weighed." — 1 Samuel 2:3 (ASV)

A God of knowledge. —The Hebrew words are placed as follows: A God of knowledge is the Lord, The Talmud quaintly comments here as follows: Rabbi Ami says, “Knowledge is highly valued, for it is placed between two Divine names; as it is written (1 Samuel 2:3), ‘A God of knowledge is the Lord,’ and therefore mercy will be denied to anyone who has no knowledge; for it is written (Isaiah 27:11), ‘It is a people of no understanding, therefore He that made them will not have mercy on them.’”—Treatise Berachoth, fol. 33,Colossians 1:0.

And by him actions are weighed. —This is one of the fifteen places counted by the Masorites where, in the original Hebrew text, instead of “lo” with an aleph, signifying not, “lo” with a vav, signifying to, or by him, must be substituted. The amended reading has been followed by the English Version. The meaning is that all human actions are weighed by God according to their essential worth. All the motives which led to them are taken into account by Him, the All-knowing, before He weighs them.