ואברכך. אני בעצמי ובכבודי: ואברכך, “I shall bless you;” I personally, not through any agent of mine.
ואגדלה שמך. שאוסיף אות אחת על שמך למנין רמ"ח איבריך ונמצא גוף שלם ושם שלם: ואגדלה שמך, “I will make your name great.” I will add a letter to your name, so that its numerical value will amount to 248, corresponding to the number of limbs in your body. Your body will then be found to be whole, matching your name.
והיה ברכה. ברכתך קודמת לברכתי שאומרים בתחלה מג"א ואחר כן מחיה המתים. ד"א והיה ברכה עד עכשיו הברכות בידי מכאן ואילך מסורות בידך ותברך כל מי שתרצה וכשרצה לברך את יצחק וראה עשו עתיד לצאת ממנו לא רצה לברך אמר אמתין עד שיבא מי שמסר לי הברכות ויברכנו אם ירצה הה"ד ויהי אחרי מות אברהם ויברך אלהים את יצחק בנו משל למלך שיש לו פרדס נאה ומסרו לאוהבו לשמור ולהשקותו מים התחיל השומר מטייל בו וראה שם שני אילנות אחד טוען סם המות ואחד טוען סם חיים וצריכין להשקות ולא היה יכול להשקות זה בלא זה אמר מה אשקה את הטוב ונמצא אני מחיה את הרע ואם לא אשקה ימות הטוב חזר ואמר אניח הכל עד שיבא בעל הפרדס ויעשה כרצונו. ד"א והיה ברכה לשון צווי שצוהו שכל מקום שילך שילמד בני אדם להכיר בוראם ולברכו וכן עשה כדכתיב לקמיה ויקרא בשם ה' שאמר לו הבורא ית' והם לא הכירוהו ולכך ויהי רעב בארץ: והיה ברכה, “your blessing will precede My blessing,” i.e. when referring to you, in their daily prayers, people will first describe Me as מגן אברהם, “the Shield of Avraham,” before they will refer to Me as מחיה מתים,”the G–d who revives the dead.” An alternate interpretation: of the words: והיה ברכה “and be a blessing;” up until now, for the last two thousand years, I have been the only source of blessing for mankind; from now on the power to bless has been transferred to you, and you can bless whosoever you see fit to provide with a blessing. This is the reason why, when wanting to transfer this power to bless to his son Yitzchok, when he foresaw prophetically that Yitzchok would sire an Esau, Avraham could not bring himself to transfer this power to Yitzchok before he died, and he left it to G–d to decide if that power were to be transferred to him. This is why we read in Genesis 25,11, that after Avraham had died G–d bestowed this power on his son Yitzchok. The matter can be illustrated by a parable. A king owned a valuable orchard which he entrusted to one of his intimate friends to look after, and to irrigate properly. The friend began to undertake his task and found that there were two trees, one of which laden with a fruit containing a deadly poison, the other with an elixir of life. Both trees needed to be irrigated, but he found that the two trees were positioned in such a way that it was impossible to irrigate the one without at the same time also irrigating the other. He said to himself that if he irrigated the beneficial tree, he would simultaneously also prolong the existence of the poisonous tree. How was he to resolve this dilemma? He therefore resolved to leave well enough alone until the next time the owner of the orchard would visit it, when he could consult with him. At that time, he would follow the owner’s instructions. Another interpretation of the words: והיה ברכה. This is not so much to be understood as a blessing itself, but as a command to become the source of blessings. Wherever his journeys would take him, he was to make it his concern to spread the knowledge about his Creator and to bless the person with whom he came into contact. This is also what Avraham did, as we know from Genesis 12,8; ויקרא בשם ה', “He proclaimed the Name of the Lord,” (praising Him). Seeing that the people did not respond to his sermons positively, G–d resorted to bringing on a famine in the land.