Hebrews 4:11 For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.
God's Word admonishes us to line up ourselves with the Word, The Lord Jesus knows our hearts. If we claim to be true, then be true and do as God's Word says. Read the Word and Study it! Don't just take the preachers' word, look if it is true...
... and know if you are worshipping in vain!