Ephesians 1:13 In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise,
He predestined us to be adopted as his sons through Jesus Christ, in accordance with his pleasure and will.
Ephesians 1:14 who is the guarantee of our inheritance until the redemption of the purchased possession, to the praise of His glory.
Second, we must have faith in Him.
Hebrews 11:6 But without faith it is impossible to please Him, for he who comes to God must believe that He is, and that He is a rewarder of those who diligently seek Him.
But everybody is claiming that they are of God. How do we know those who are not?
Titus 1:16 They profess to know God, but in works they deny Him, being abominable, disobedient, and disqualified for every good work.
2 Peter 2:10 This is especially true of those who follow the corrupt desire of the sinful nature and despise authority. Bold and arrogant, these men are not afraid to slander celestial beings;
Do you know that even angels are afraid of cursing the glorious beings in heaven?
2 Peter 2:11 yet even angels, although they are stronger and more powerful, do not bring slanderous accusations against such beings in the presence of the Lord.
Believing that there is no God is therefore not a guarantee of inheritance.