Sources

Christian blogs are a succinct and helpful way to proclaim the truth. I have read thousands of blog posts and have tried to curate the best ones on any given topic above. Most of the articles are curated from the following blogs, which I recommend highly.

AlbertMohler.com
Blog of Dr. Al Mohler, president of The Southern Baptist Theological Seminary.  He gives a radio program of the daily briefing that sums of the events in the world and in America, and reads them in light of the Christian worldview.  He writes and speaks insightfully on topics of greatest urgency such as homosexuality/same-sex relationships, religious freedoms in America, and liberal theology in education.

Challies.com
Blog of Tim Challies, pastor of Grace Fellowship Church in Toronto, Ontario.  He blogs daily about a variety of topics, including content like Christian news, beautiful videos of the cosmos,  Kindle deals for Christian books, free sponsored giveaways from publishing companies like Crossway, and Christian book reviews.  He speaks practically on many topics in the Christian life, in particular gospel-driven productivity, integrating technology wisely into the Christian life, and fighting pornography in the church.  I must admit that much of this blog is patterned after his; he's a good example to follow.

The CrippleGate
Blog of four pastors from the states of California and Virginia, and the country of South Africa.  Their content ranges widely, from commentary on current events, to Bible-nerd word studies, to comedic content on single Christian men, to stories from church history, to expositions of certain passages of Scripture.  All of it is quite good, and they try to break up the more technical posts with lots of [albeit strange] pictures.

Desiring God
The ministry site started by John Piper.  It has all of his sermons (over 30 years) preached at Bethlehem Baptist Church in Minneapolis, Minnesota, as well as access to most of his books and his articles for free.  Nowadays, the main activity is within the blog.  There are many other writers in addition to Piper that contribute, one of the best being Tony Reinke.  The strongest content is on Christian hedonism and finding ultimate contentment in Christ, and perhaps the most unique content is engaging with things like TV shows, sexuality, particular issues facing postmoderns from a definite Christian perspective.  I've also found that the content seems targets to target 20s-40s.

Grace to You
The ministry site of John MacArthur, pastor of Grace Community Church in Sun Valley, California.  This is the repository of over 40 years of ministry — sermons, radio broadcasts, books, articles, pamphlets, blog posts.  MacArthur has preached through every verse of the New Testament to his church, and his clarity and completeness is simply unparalleled.  In addition, the comprehensiveness of such a long-tenure and such a wide exposition is second to none; if you have a question about a particular verse of the Bible, the answer is unequivocally here.

Ligonier Ministries
The ministry site of R.C. Sproul, pastor of Saint Andrew's Chapel in Sanford, FL.  This is Reformed theology in the purest sense.  Sproul has been in ministry longer than MacArthur - over half a century! - and the quality and experience shows mightily.  The blog's strength is it's accessibility, helpfulness, applicability, and persistent quality even while dealing with complex theological subjects.  This has quickly become one of my favorite blogs to read, time and time again.