Purity, even purity of heart, is the main thing to be aimed at. We need to be made clean within through the Spirit and the Word, and then we shall be clean without by consecration and obedience. There is a close connection between the affections and the understanding: if we love evil we cannot understand that which is good. If the heart is foul, the eye will be dim. How can those men see a holy God who love unholy things?
What a privilege it is to see God here! A glimpse of Him is heaven below! In Christ Jesus the pure in heart behold the Father. We see Him, His truth, His love, His purpose, His sovereignty, His covenant character, yea, we see Himself in Christ. But this is only apprehended as sin is kept out of the heart. Only those who aim at godliness can cry, “Mine eyes are ever towards the Lord.” The desire of Moses, “I beseech thee, show me thy glory,” can only be fulfilled in us as we purify ourselves from all iniquity. We shall “see him as he is,” and “every one that hath this hope in him purifieth himself.” The enjoyment of present fellowship and the hope of the beatific vision are urgent motives for purity of heart and life. Lord, make us pure in heart that we may see Thee!
[from Faith’s Checkbook by Charles H. Spurgeon]