lifted up his eyes. Figure of speech Pleonasm, for emph, (App-6).
looked. See note on Genesis 13:14.
behold. Figure of speech Asterismos.
a ram. Some Codices (with Samaritan Pentateuch, The Targum of Jonathan ben Uzziel, Septuagint, and Syriac) read "one ram", i.e.. solitary ram.
a thicket. Hebrew the thicket.
in the stead. Here is the doctrine of substitution, clearly stated.