This is the first appearance of the Lord to anyone in the Bible, the first time we read of an appearance. Previously, the Lord had spoken either in a vision or dream or audibly to Abraham, but now he appears to him.
Remember the places of special visitation, great answers to prayer, wonderful events. Not by building monuments – we can well understand why they did that – but remember them to strengthen your own faith. Remember places where you had very significant spiritual appearances or blessings of God to you; not literal appearances, but God dealt with you. Remember the place. If you had a sudden conversion, remember the place. Remember the place when your eyes were first open to some great truth, when you were blessed with a particularly wonderful answer to prayer which delivered you from a thousand fears. Perhaps you have the opportunity to visit and to pray and to give thanks. Perhaps it'll make you much more loyal to people who've been instrumental in places that have been instrumental in your life and more prayerful for them, too. Abram builds an altar of gratitude and thanksgiving. ‘He removed from thence unto a mountain on the east of Bethel, and pitched his tent, having Bethel on the west, and Hai on the east: and there he builded an altar unto the LORD, and called upon the name of the LORD.’ So another stage of the journey takes place and more worship, another memorial, and so it should be with us. Every stage of the journey God moves us from one place to another, a great turning point in life, and there we make a memorial and we remember God's goodness to us up to this point and commit ourselves to him for the next phase of the earthly journey. This father of the faithful is always worshipping and building his altars.