Matthew Henry on Exodus 34:28-35

Near and spiritual communion with God improves the graces of a renewed and holy character. Serious godliness puts a lustre upon a man's countenance, such as commands esteem and affection. The vail which Moses put on, marked the obscurity of that dispensation, compared with the gospel dispensation of the New Testament. It was also an emblem of the natural vail on the hearts of men respecting spiritual things. Also the vail that was and is upon the nation of Israel, which can only be taken away by the Spirit of the Lord showing to them Christ, as the end of the law for righteousness to every one that believeth. Fear and unbelief would put the vail before us, they would hinder our free approach to the mercy-seat above. We should spread our wants, temporal and spiritual, fully before our heavenly Father; we should tell him our hinderances, struggles, trails, and temptations; we should acknowledge our offences.