Who and what is
This is the name of a biblical man and a place (named after him). His name appears 128 times in Scripture. In later times, the name “Isaac” was used as a synonym for Israel, or the kingdom of the ten tribes (see: Amos 7:9, 16).
Son of Abraham
He was the longest lived of the 3 patriarchs (Genesis 21:1-3). He was circumcised when 8 days old (4-7); and when he was probably 2 years old a great feast was held in connection with his being weaned.
After the death and burial of his father he took up his residence at Beer-lahai-roi (25:7-11), where his two sons, Esau and Jacob, were born (21-26), the former of whom seems to have been his favorite son (27,28).
Because of a famine (Genesis 26:1), Isaac went to Gerar, where he lied about his relation to Rebekah, imitating the conduct of his father in Egypt (12:12-20) and in Gerar (20:2). The Philistine king rebuked him for his prevarication.
After sojourning for some time in the land of the Philistines, he returned to Beersheba, where God gave him fresh assurance of covenant blessing, and where Abimelech entered into a covenant of peace with him.
In the New Testament, reference is made to his having been “offered up” by his father (Hebrews 11:17; James 2:21), and to his blessing his sons (Hebrews 11:20). As the child of promise, he is contrasted with Ishmael (Romans 9:7,10; Galatians 4:28; Hebrews 11:18).
“at once a counterpart of his father in simple devoutness and purity of life, and a contrast in his passive weakness of character, which in part, at least, may have sprung from his relations to his mother and wife. After the expulsion of Ishmael and Hagar, Isaac had no competitor, and grew up in the shade of Sarah's tent, moulded into feminine softness by habitual submission to her strong, loving will.”
His life was so quiet and uneventful that it was spent…
“within the circle of a few miles;
so guileless that he let Jacob overreach him rather than disbelieve his assurance;
so tender that his mother's death was the poignant sorrow of years;
so patient and gentle that peace with his neighbors was dearer than even such a coveted possession as a well of living water dug by his own men;
so grandly obedient that he put his life at his father's disposal;
so firm in his reliance on God that his greatest concern through life was to honor the divine promise given to his race.” (—John Cunningham Geikie, Hours with the Bible, or, the Scriptures in the Light of Modern Discovery and Knowledge (1896-97)
Lineage, from Creation to Abraham
God → ADAM → Seth → Enos → Cainan → Mahalaleel → Jared → Enoch → Methuselah → Lamech → NOAH → Shem → Arpachshad → Shelah → EBER (founder of the Hebrew race) → Peleg → Reu → Serug → Nahor → Terah → Abraham → ISAAC