Commentary for Genesis 22:7

And he said, "Father," etc.: But Yitzchak had not yet said anything to him, but rather just called him, "Father," and was quiet. This was because Yitzchak felt that it was his father's will to sacrifice him as a burnt-offering. So he thought, "If so, he does not have mercy upon me like the mercy of a father upon his children, and has become cruel towards me." As he did not yet know that it was the will of his Creator. Hence he called him, "Father," to test him; [to see] whether he would answer him, since it was still affixed in his heart that he was his son; or whether he had already removed him from his heart as if he were not his son. As through this, he wanted to know who would be slaughtered. And when he answered him, "Here I am, my son," and indicated to him that all of his longings towards him were still [there], he said to him, if so, "where is the lamb?" So he said to him, "God will see to the lamb for Him for the burnt-offering, my son"; it was not I who chose you, but God - and you and I both are obligated to honor Him. Then, "the two of them went together" - with one intent. This is excluding until now - they were [then] differing in their minds.

הנני בני, with a dagesh also in the second letter נ.

And he said, "Father": And he did not immediately ask, "Where is the lamb." As he sensed something wonderous, but he did not find the heart to ask until after reflecting upon the answer of his father - whether it would be with a pleasant countenance and love. Therefore when he answered him, "Here I am, my son" - which was a loving answer - he then asked to know.