In A Month of Sundays: 31 Meditations on Resting in God, Glenda Mathes states her purpose: "While we worship and rest on Sunday, we must also rest daily by trusting our triune God and obeying His timeless Word. Each of these devotions helps readers do that through a recommended Scripture reading reference, a focus verse (or verses), a meditation, and questions aimed at stimulating personal reflection," (p. viii).
This book provides a short 3 or 4 page daily devotion on a focused verse followed by 3 open-ended questions for 31 days. Ms. Mathes concludes that "we've looked at key Scripture texts that affirm God's creation ordinance for Sabbath rest, confirm the biblical command for daily rest, and anticipate the guaranteed promise of eternal rest," (146). Even though her stated main devotional focus is on the biblical concept of Sabbath rest, each day's devotional content does not explicitly tie in with this theme; sometimes the idea of rest only comes as an afterthought in the questions for reflection. A Month of Sundays is definitely written to the Christian reader since there is no Gospel presentation given.
The author usually quotes from the King James Bible, except on page 40 where she quotes the same Job passage from the English Standard Version (ESV) and on page 84 where she quotes mostly from the King James for Mark 10:43-45, but replaces the word 'minister[ed]' with the words 'serve[d] or servant'. Unfortunately, she did not explain why she was making those changes or what point she was trying to make that the King James Bible did not readily support. On page 50 she quotes Psalm 90:14 from the ESV so that she can compare the language to Lam. 3:22-23 in the King James Bible. This comparison allows her to focus on the word 'morning' (which is not found in the quoted focus verse) as she ends her devotional look at God as a dwelling place. Bringing in another Bible version so that she can change the words to help make her point does not lend to the credibility of her commentary.
On Day 12 Ms. Mathes looks at Psalm 121 and discusses the "wonderful image of God as a protective covering," (p. 55). She says: "As God's image bearers, we are called to care for others and provide for their welfare," (p. 55). The author gives no biblical reference for this statement, but gives an example of Cain and Abel and notes that "Cain...failed to keep his brother," (p. 55). From John Gill's Exposition of the Entire Bible, Mr. Gill shows that Cain's question of 'Am I my brother's keeper?' (Gen. 4:9) "...was very saucily and impudently spoken...that God should put such a question to him, since he knew he had not the charge of his brother, and his brother was at age to take care of himself; and if not, it rather belonged to God and his providence to take care of him, and not to him." This psalm clearly states that the Lord is our keeper (verse 5) and Mr. Gill affirms that the care of Abel belonged to the providence of God and not his brother Cain. Therefore, the author erroneously applies Psalm 121 to the individual believer.
From the title of this book, I expected a more in-depth look of the Sabbath rest found in Genesis, Exodus, & Hebrews. If that's your expectation as well, then I would recommend The Holy Sabbath by A.W. Pink. If you're just looking for a simple devotional that includes the idea of rest, then this book adequately serves that purpose.
I found the last half of A Month of Sundays more helpful than the first, and I was especially encouraged by the content of day 17 "Light Yoke", day 26 "God's Peace", and day 27 "Sound Mind". Overall the content is mostly sound (except as noted above) and the material thought-provoking at times. Therefore, I recommend this book for any Christian as part of his devotional routine.
"There remaineth therefore a rest to the people of God. For he that is entered into his rest, he also hath ceased from his own works, as God did from his. Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief," (Heb. 4:9-11).