Us believing is the work of God.
Acts 16:31 doesn't say men are commanded to believe. It says, 'Believe in the Lord Jesus and you will be saved'. Like I said, the gift is the sacrifice for former sins for all who repent and believe. For instance, if a man repents and he believes the word of the Lord today, then his former sins will be forgotten. However the teachings of Jesus are for life going forward. Jesus said
Matthew 7:24
“Every one then
who hears these words of mine
and does them will be like a wise man
who built his house upon the rock;
Matthew 7:26
And every one
who hears these words of mine
and does not do them will be like a foolish man
who built his house upon the sand
John 5:24
Truly, truly, I say to you,
he who hears my word and believes him
who sent me, has eternal life;
he does not come into judgment, but has passed from death to life.
So if you believe this, then you will keep his commandments (because he said if you love me you will keep my commandments John 14:15) And likewise store up treasure, because he said store up treasure, 'but lay
up for yourselves
treasures in heaven, where neither moth nor rust consumes and where thieves do not break in and steal. For where your
treasure is, there will your heart be also. Mt. 6:20-21