Moyes quit the Toffees in the summer to sign a six-year-contract with the Old Trafford outfit after being hand-picked for the post.
Ferguson said, "He (Moyes) phoned me around February for some advice about his contract, they were pushing him to sign a new contract.
"I knew in myself I was going to retire, so I’m thinking If he signed a contract it would be more difficult for us.
"I said to him you’ve had ten years there that’s long enough, you’ll get a bigger club.
"I kept phoning him to make sure he wasn’t going to sign a new contract.
"We had to wait till the league was decided, once the league was decided I got David over to the house and I think he thought we were going to talk about his contract again, but I said look I want you to take over."
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