"Ex opere Operato"- “By the performance of the action”. That phrase conveys the Roman Catholic teaching that the sacraments bring blessings to people simply because they are performed. (Think of masses being performed for the dead.)
28.5 Although it be a great sin to contemn or neglect this ordinance, yet grace and salvation are not so inseparably annexed unto it as that no person can be regenerated or saved without it, or that all that are baptized are undoubtedly regenerated.
28.6 The efficacy of baptism is not tied to that moment of time wherein it is administered; yet, notwithstanding, by the right use of this ordinance, the grace promised is not only offered, but really exhibited and conferred by the Holy Ghost, to such (whether of age or infants) as that grace belongeth unto, according to the counsel of God’s own will, in His appointed time.
28.7 The sacrament of baptism is but once to be administered to any person.
5 not by works of righteousness which we have done, but according to His mercy He saved us, through the washing of regeneration and renewing of the Holy Spirit, (Titus 3:5)
Resources:
Sola Fide Compromised? Martin Luther and the Doctrine of Baptism by Rev. D. Patrick Ramsey
What is Baptism and Does it Save? by John Piper
Is Baptism Necessary for Salvation? by Gregory Koukl
Baptism and Galatians 3:27 by Matt Slick
Baptismal Regeneration by C.H. Spurgeon
Is Baptism Necessary for Salvation? - Acts 2:38; Galatians 2:16; Ephesians 2:8-9; Philippians 3:9 by Dr. John MacArthur
Does Baptism Save You? (1 Peter 3:21; Acts 2:38 by Jeremiah Johnson
Does Baptism Save? (1 Peter 3) by Sam Storms
Calvin and Baptism: Baptismal Regeneration or the Duplex Loquendi Modus? by Jim Cassidy
Heidelberg 71: What’s Baptism Got To Do With It? by Dr. Scott Clark
Strangers And Aliens (17b): As It Was In The Days Of Noah (1 Peter 3:18–22) by Dr. Scott Clark
The Washing of Regeneration by Ligonier Ministries
Baptism and Regeneration by Ligonier Ministries
Baptismal Regeneration: A Critique by Dr. H. Wayne House
Does The Nicene-Constantinopolitan Creed Require Baptismal Regeneration? by Dr. Scott Clark
A Brief Rebuttal of Baptismal Regeneration by Dr. James White
What did some of the Reformers believe about Baptismal Regeneration? by Scott Bushey
My Objection to Baptismal Regeneration by Bobby Grow
Baptism Now Saves Us by Martyn McGeown
Multimedia:
What would you say in response to the doctrine of baptismal regeneration? by Dr. R.C. Sproul
The Ancient Understanding of Baptism as Washing and Regeneration by Reformed Forum
Baptismal Regeneration by Dr. James White
Regeneration and Baptism by Dr. John Piper
Biblical Sacraments v Rome by Patrick Hines
How Does Baptism Save Us? by John M. Otis
Does Water Baptism Save? by Dr. John MacArthur
Books:
Baptismal Regeneration Refuted & Spiritual Regeneration Explained (Ebook) by Joseph Turnbull
Baptismal Regeneration by C.H. Spurgeon