The Gift of God is Eternal Life in Christ Jesus our Lord

"The end of [sin] is death. Though the way may seem pleasant and inviting, yet the end is dismal: at the last it bites; it will be bitterness in the latter end…. Death is as due to a sinner when he hath sinned as wages are to a servant when he hath done his work. This is true of every sin…. Death is the wages of the least sin. Sin is here represented either as the work for which the wages are given, or as the master by whom the wages are given; all that are sin's servants and do sin's work must expect to be thus paid. If the fruit be unto holiness, if there be an active principle of true and growing grace, the end will be everlasting life – a very happy end! – Though the way be up-hill, though it be narrow, and thorny, and beset, yet everlasting life at the end of it is sure. So, the gift of God is eternal life. Heaven is life, consisting in the vision and fruition of God; and it is eternal life, no infirmities attending it, no death to put a period to it. This is the gift of God. The death is the wages of sin, it comes by desert; but the life is a gift, it comes by favor. Sinners merit hell, but saints do not merit heaven…. It is Christ that purchased it, prepared it, prepares us for it, preserves us to it; he is the Alpha and Omega, All in all in our salvation." – Matthew Henry