John Knox, descended from the Knoxes of Ranferly, was born in Giffordgate, Haddington, between 1505-1515 and his father was probably a farmer. From the Grammar School he went in 1522 to the University of Glasgow, and then to the University of St Andrews where he was under the celebrated John Major, then Principal Regent or Professor of Philosophy and Divinity. He got the degree of Master of Arts very young, specialising in philosophy and polemic divinity. After leaving college he passes out of view for ten or a dozen years. About this time he would seem to have taken priest's orders, and to have been for up to ten years connected with one of the religious establishments in the neighbourhood of Haddington. In 1543 he describes himself as a notary.
This map is from 1819. You can see Knox home marked; it is the house across the river from the Parish Church, furthest on the right.