John Lightfoot on Luke 11:4

[And lead us not into temptation.] I am much deceived if this petition is not amongst other things, and indeed principally, and in the first place, directed against the visible apparitions of the devil, the evil one: as also his actual obsessions: by which the phrase of God's 'leading us into temptation' is very much softened.

The doxology, 'For thine is the kingdom,' &c., is left out, because it was our Saviour's intention in this place to deliver to them a form of prayer merely petitionary; for which very same reason also, Amen is omitted too. For he shall say Amen at thy giving of thanks: and indeed they commonly ended all their prayers, even those that consisted most of petition, with thanksgiving and benediction; concluding in this manner, "Blessed be thou, O Lord, who hast thus done, or thus commanded," or the like; and then was it answered by all, Amen. This we may observe in those Psalms that conclude any portion of that book, and end with Amen: upon what subject soever the Psalmist is engaged, either throughout the whole psalm, or immediately before the bringing forth of Amen, still he never doth mention Amen without some foregoing doxology and benediction, "Blessed be the Lord God, &c., Amen and Amen." In St. Matthew, therefore, we find Amen, because there is the doxology: in St. Luke it is wanting, because the doxology is so too. You may see more of this in notes upon Matthew 6.