Officially opening the £1.5 million Lubavitch Children's Centre in Stamford Hill on Monday, Lord Sacks said he became a rabbi because of the Lubavitch movement.
The Chief Rabbi told more than 150 guests: "In April 1968, I attended the opening of the first Lubavitch building with others and it was the connection made at that wonderful occasion that drew myself and Elaine [Lady Sacks] into the ambit of Chabad Lubavitch. And it changed our lives. I would not be a rabbi, let alone the Chief Rabbi, if Lubavitch did not hold out its hand to me.
"We are as young as our highest priority - our children. The face of the Jewish future is the faces of those beautiful children."
The centre houses a nursery, family services, adult education facilities and the Lubavitch Central Library, stocked with 15,000 books.