When I went to the CREC link you provided, it read the following: "The Communion of Reformed Evangelical Churches (CREC), formerly the Confederation of Reformed Evangelical Churches, was founded in 1998 as a body of churches that hold to Reformed (Calvinistic) theology … "
Calvinism is a section of Protestantism that follows the teachings and beliefs of Protestant Giant John Calvin, along with other late reformists.
The acronym "TULIP" is used to define the five main pillars of the Calvinistic view (a view that many Christians do not fully agree with, but agree that people who do are still indeed Christians, because at the base of both views, the same way of salvation is kept).
TULIP can be described as the following according to the "Calvinist Corner":
Total Depravity (also known as Total Inability and Original Sin) Unconditional Election Limited Atonement (also known as Particular Atonement) Irresistible Grace Perseverance of the Saints (also known as Once Saved Always Saved)
In a nutshell, the first part is something that nearly all Christians believe, and that is that we are completely unable to save ourselves...and... that we--in and of ourselves--are completely unable to refrain from sin. We need the grace of God. Verses on this subject can be found: [Eph. 1:1-11; Rom. 8:29; 9:9-23; John 6:28-29; Acts 13:48; Phil. 1:29; and John 1:12-13].
The second part (Unconditional Election), is the belief that God chooses people who he will save not because of anything they have done, how they appear, or how God feels. Additional reading: [Eph. 1:4-8; Rom. 9:11; and Rom. 9:15, 21].
The third pillar (Limited Atonement) states that Jesus's death is for all people, but not all will/can accept. As the Calvinist Corner puts it "Though Jesus’ sacrifice was sufficient for all, it was not efficacious for all." Supporting verses: [Matt. 25:32-33; Matt. 26:28; John 10:11, 15; John 17:9; Acts 20:28; Eph. 5:25-27; and Isaiah 53:12].
The fourth belief is the belief of Irresistible Grace. This states that we cannot resist God's grace. If he offers us salvation, we are literally unable to say no. Bible verses [Philippians 2:12-13; Romans 9:16; John 6:28-29; Acts 13:48; John 1:12-13; and John 6:37].
The fifth (and final) belief (Perseverance of the Saints (Once saved always saved)). Christians (Calvinists) believe this because Jesus has died, God has offered, God has saved...and we cannot refuse his grace (as stated in point 4). If you believe all previous Calvinistic points, you must logically follow this point to. Supporting verses [John 10:27-28; John 6:47; Romans 8:1; 1 Corinthians 10:13; and Phil. 1:6].