Exodus 6:3

וארא AND I APPEARED — to the patriarchs. באל שדי BY THE NAME OF GOD ALMIGHTY — I made certain promises to them and in the case of all of these I said unto them, “I am God Almighty”. ושמי ה׳ לא נודעתי להם BUT BY MY NAME THE LORD WAS I NOT KNOWN TO THEM — It is not written here לא הודעתי [My name the Lord] I did not make known to them, but לא נודעתי [by My name, the Lord], was I not known [unto them] — i. e. I was not recognised by them in My attribute of “keeping faith”, by reason of which My name is called ה׳, which denotes that I am certain to substantiate My promise, for, indeed, I made promises to them but did not fulfill them [during their lifetime].

וָאֵרָ֗א אֶל־אַבְרָהָ֛ם אֶל־יִצְחָ֥ק וְאֶֽל־יַעֲקֹ֖ב בְּאֵ֣ל שַׁדָּ֑י וּשְׁמִ֣י יְהֹוָ֔ה לֹ֥א נוֹדַ֖עְתִּי לָהֶֽם׃

and I appeared to Avraham, to Yiżĥaq, and to Ya῾aqov, by the name of God Almighty, but by my name, The Lord, I was not known to them.