"Bondservants, be obedient to those who are your masters according to the flesh, with fear and trembling, in sincerity of heart, as to Christ; 6 not with eyeservice, as men-pleasers, but as bondservants of Christ, doing the will of God from the heart..." Ephesians 6:5-6

It's impossible to please God without faith, but worst than that is the lack of sincerity. This has been the reason for many weak 'Christians' nowadays.