God said through Paul, "I...implore you to walk in a manner worthy of the calling with which you have been called." That sounds pretty important, huh? Well He goes on to say,"being diligent to preserve the unity of the Spirit in the bond of peace." (All verses from Eph 4:1-6)
That's FOUNDATIONALLY important! So what things is God looking for? Well they're in the next two verses. Which of these are you comfortable telling people, "Eh, God doesn't care about THAT one. You don't have to believe it?"
1.)There is one body
2.) and one Spirit,
3.) one hope of your calling;
4.) one Lord,
5.) one faith,
6.) one baptism,
7.) one God and Father of all who is over all and through all and in all.
Which one of those are you willing to leave out when teaching someone about God? Are any of them "not that important?"