The scripture you reference states one was sealed after believing something. (Eph 1:13)
That something was the word of truth, the gospel of salvation. Consider that is exactly what the Apostle Peter's instructions entailed.
After Peter spoke of Jesus' death, burial and resurrection the crowd believed him and obeyed the word of truth, in fact the gospel of salvation: they repented, got baptized in the name of the Lord Jesus and received the gift of the Holy Ghost. The scripture goes on to state that 3,000 were saved that day alone.
Acts 2:40-41
"And with many other words did he testify and exhort, saying, Save yourselves from this untoward generation.
Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls."
The same components (belief, repentance, water baptism and receiving the Holy Ghost) were required of individuals, Gentiles, Samaritans and Jews. These are detailed in many other examples recorded in the Gospels, Acts and Paul's Epistles.
That something was the word of truth, the gospel of salvation. Consider that is exactly what the Apostle Peter's instructions entailed.
After Peter spoke of Jesus' death, burial and resurrection the crowd believed him and obeyed the word of truth, in fact the gospel of salvation: they repented, got baptized in the name of the Lord Jesus and received the gift of the Holy Ghost. The scripture goes on to state that 3,000 were saved that day alone.
Acts 2:40-41
"And with many other words did he testify and exhort, saying, Save yourselves from this untoward generation.
Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls."
The same components (belief, repentance, water baptism and receiving the Holy Ghost) were required of individuals, Gentiles, Samaritans and Jews. These are detailed in many other examples recorded in the Gospels, Acts and Paul's Epistles.