The Trinity holds you securely by God's power

Your eternal security is permanent. 

Once you are saved God eternally seals you with the Holy Spirit indwelling you. 

John 6:37-40

All that the Father gives me will come to me, and whoever comes to me I will never cast out.  39 And this is the will of him who sent me, that I should lose none he has given me, but raise it up on the last day. For this is the will of my Father, that everyone who looks on the Son and believes in him should have eternal life, and I will raise him up on the last day.”

John 10:27-29

 My sheep hear my voice, and I know them, and they follow me. I give them eternal life, and they will never perish, and no one will snatch them out of my hand. My Father, who has given them to Me, is greater than all; and no one is able to snatch them out of My Father’s hand.

Luke 10:20 

... rejoice that your names are written in heaven.”

Revelation 13:8 

And all who dwell on earth ... whose name has not been written before the foundation of the world in the book of life of the Lamb who was slain

Philippians 1:6

For I am confident of this very thing, that He

who began a good work in you will perfect it until the day of Christ Jesus.

"1:6 He.. will perfect it."

The Greek verb translated "began" is used only here and in Gal 3:3-both times in reference to salvation itself. When God begins a work of salvation in a person, He finishes and perfects that work. Thus the verb "will perfect" points to the eternal security of the Christian (Ro 5:10;

8:29-39; Eph 1:13, 14; Heb 7:25; 12:2).

"day of Christ Jesus." This phrase is not to be confused with the "Day of the Lord" which describes final divine judgment and wrath (cf. Is 13:9; Joel 1:15; 2:11; 1Th 5:2; 2Pe 3:10). "Day of Christ Jesus" is also called the

"day of Christ" (v. 10; 2:16) and the "day of our Lord Jesus Christ" (1Co 1:8), which 👉looks to the final salvation, reward, and glorification of believers. Cf. 1Co 3:10-15; 4:5; 2Co 5:9, 10.

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Study The "eternal security of the believer" here, (under bold heading section).

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Footnotes:

 The MacArthur Study Bible