The Westminster Shorter Catechism:
Q29 – How are we made partakers of the redemption purchased by Christ?
A29 – We are made partakers of the redemption purchased by Christ, by the effectual application of it to us, (John 1:11–12) by his Holy Spirit. (Titus 3:5–6)
Q30 – How doth the Spirit apply to us the redemption purchased by Christ?
A30 – The Spirit applieth to us the redemption purchased by Christ, by working faith in us, (Eph. 1:13–14, John 6:37–39, Eph. 2:8) and thereby uniting us to Christ in our effectual calling. (Eph. 3:17, 1 Cor. 1:9)
Q31 – What is effectual calling?
A31 – Effectual calling is the work of God’ s Spirit, (2 Tim. 1:9, 2 Thess. 2:13–14) whereby, convincing us of our sin and misery, (Acts 2:37) enlightening our minds in the knowledge of Christ, (Acts 26:18) and renewing our wills, (Ezek. 36:26–27) he doth persuade and enable us to embrace Jesus Christ, freely offered to us in the gospel. (John 6:44–45, Phil. 2:13)