According to the author the only way to resist the tendency to drift is to give more earnest heed to the things we have heard.
In the parable of the sower Jesus describes this phenomenon by saying that if any one hears the word and does not understand it, then the wicked one comes and snatches away what was sown in his heart,and another one will immediately receives with joy and endures for a while but but when tribulations, persecution,cares of this world,the deceitfulness,riches and desires for other things will drift us away from the gospel