Ambrose (c. 339-97) in a sermon to his congregation:
"‘The books of the heavenly Scriptures are good pastures, by which we are fed by daily reading, by which we are renewed and refreshed, when we taste the things that are written, or ruminate frequently upon that which has been tasted. Upon these pastures the flock of the Lord is fattened."
Latin text: Bona etiam pascua libri sunt Scripturarum coelestium, in quibus quotidiana lectione pascimur, in quibus recreamur ac reficimur; cum ea quae scripta sunt, degustamus, vel summo ore libata frequentius ruminamus. His pascuis grex Domini saginatur. Psalmus CXXXIV (119), Sermo Quartus Decimus, §2, PL 15:11390-1391."
Source:For translation, see William Goode, The Divine Rule of Faith and Practice, 2nd ed., (London: John Henry Jackson, 1853), Vol. 3, pp. 261-262. .
For an excellent compilation of quotes of the Church fathers teaching on the primacy, sufficiency and ultimate authority of Scripture, get a copy of Holy Scripture:The Ground and Pillar of Our Faith Vol III- The Writings of the Church Fathers Affirming the Reformation Principle of Sola Scriptura.