If you are looking for an evangelical commentary on chapters 18-50 of Genesis, then Genesis 18-50, by Victor P. Hamilton published by Eerdmans Publishers is the commentary you are looking for. While this is an older volume it is one of the greatest volumes in the entire series, the New International Commentary On the Old Testament series, a series which is synonymous with superior exegesis and excellent application, this volume continues the long legacy. This volume is one of the most articulate and practical modern commentaries on the first book of the Pentateuch.
This the second volume on the book Genesis covers only chapters 18-50, begins without the typical introductory section, for it is covered in the first volume instead Hamilton jumps strait into the 18th chapter. As with most technical commentaries, and with all works in the New International Commentary of the Old Testament series, Hamilton dives headlong into the theological elements of the specific biblical book, in this case Genesis. Hamilton is brilliant in his exegesis and should be a great aid to any Minister preaching exegetically through the book of Genesis.
With regard to the commentary section of this second volume Hamilton sends just shy of 800 pages. The thoroughness in which Hamilton goes through must be commended. He diligently gives commentary to the textual notes and the Hebrew text itself when nessessary. Sporadically Hamilton also adds comments on biblical Theology and application and devotional implications. This trait is extremely helpful to the pastor as well as scholar.
With regard of recommending, Genesis 18-50, to others I would whole heartily recommend this commentary to students of scripture, with one caveat. By this I mean I recommend this work to Pastors, Bible Teachers, Bible College Students, there is enough scholarly weight to this work to understand a particular issue in the text while giving aid to pastors in preaching the text. There are many commentaries about the first book of the Pentateuch available at this moment but Genesis 18-50, of the New International Commentary on the Old Testament series is a giant leap above all other commentaries on this book of the Bible.
These books was provided to me free of charge from Eerdmans in exchange for an unbiased, honest review.