‘וְלִבְכֹּתָהּ’ – “and he wept for her” (Chayei Sarah 23:2)
The Baal Haturim says that there is a small ‘כּ‘ to explain that he only cried a bit because she was old.
The Bikurei Avraham asks, ‘How this can be the explanation of וְלִבְכֹּתָהּ’? The Torah is emphasizing that he only cried a bit for his deceased wife – is this a praise of Avraham?!
Furthermore, this was Sarah Imeinu – whilst Avraham converted many people, it was she who converted all the women, she was a great prophetess of her own right, she was the first of the matriarchs, all of whom experienced regular miracles. In an instant this was lost – was it not necessary to weep without end at the loss of such an important person? At the passing of both Moshe and Aharon at the ages of 120 and 123 respectively, the entire nation had a 30 day mourning period – how are we to understand that Avraham did not greatly mourn his wife?
In truth, the Torah is trying to tell us what a special and unique person Avraham Avinu was. When he got back from the Akeida, he found his wife had passed, and knew it had happened when she’d heard about the Akeida – ‘ונסמכה מיתת שרה לעקידת יצחק’ (Rashi 23:2)
The way the Yetzer Hara works is that he doesn’t just dissuade us from trying to do something – he approaches us even after we’ve achieved our goal. He tried to manipulate Avraham into regretting the Akeida that was the cause of his wife’s death.
What Avraham did was distance himself from such thoughts – he justified her death to himself (refer to the above quote from the Ba’al Haturim) by saying her time had come to die anyway because ‘she was old’. The fact that the Torah publicized that he wept briefly for his deceased wife is indeed a huge praise for Avraham.
This methodology used by the Yetzer Hara – discourage from performing, bad intentions while performing, haughtiness or regret after – all cause a person to forfeit any reward due for performing Mitzvahs. It has no value in G-D’s eyes, since it has no value in man’s eyes. This is what we pray for in Ma’ariv every day when we say “v’hoser satan milfaneinu” (“before us [our action] and after us”).