You’re adding to the word yet again as you cannot keep your bias out of it, you have to mitigate the meaning to arrive at your error.
Which is the earnest of our inheritance,.... The incorruptible and never fading one in heaven, or the heavenly kingdom; this is the Father's gift, his bequest, and belongs only to children; it comes to them through the death of the testator, Christ, and is for ever; and of this the Spirit of God is the pledge and earnest: an earnest, is what confirms an agreement, and assures the right to the thing agreed to, and is a part of it, and lesser than it, and is never returned; so the Spirit of God certifies the right to the heavenly inheritance, as well as gives a meetness for it; he is the firstfruits of eternal glory and happiness, and of the same kind with it; and as he is enjoyed in measure by the saints now, is lesser than the communion which they shall have with him, and with the Father, and the Son, hereafter, for the best things are reserved till last; and being once given into the heart as an earnest, he always continues, he never removes more, or is ever taken away: John Gill