"And these words which I command thee this day, shall be _in thine heart_"--at the very source of all the issues of life. This is peculiarly precious. Whatever is in the heart comes out through the lips and in the life. How important, then, to have the heart full of the Word of God--so full, that we shall have no room for the vanities and follies of this present evil world. Thus shall our conversation be always with grace, seasoned with salt. "Out of the abundance of the heart the mouth speaketh." Hence we can judge of what is in the heart by what cometh out of the mouth. The tongue is the organ of the heart--the organ of the man. "A good man out of the good treasure of the heart bringeth forth good things; and an evil man out of the evil treasure bringeth forth evil things." When the heart is really governed by the Word of God, the whole character reveals the blessed result. It must be so, inasmuch as the heart is the main-spring of our entire moral condition; it lies at the centre of all those moral influences which govern our personal history and shape our practical career. In every part of the divine volume, we see how much importance God attaches to the attitude and state of the heart, with respect to Him or to His Word, which is one and the same thing. When the heart is true to Him, all is sure to come right; but on the other hand, we shall find that where the heart grows cold and careless as to God and His truth, there will, sooner or later, be open departure from the path of truth and righteousness. There is, therefore, much force and value in the exhortation addressed by Barnabas to the converts at Antioch--"He exhorted them all, that with _purpose of heart_ they would cleave unto the Lord." How needful then, now, always! This "purpose of heart" is most precious to God. It is what we may venture to call the grand moral regulator. It imparts a lovely earnestness to the Christian character which is greatly to be coveted by all of us. It is a divine antidote against coldness, deadness, and formality, all of which are so hateful to God. The outward life may be very correct, and the creed may be very orthodox; but if the earnest purpose of heart be lacking--the affectionate cleaving of the whole moral being to God and His Christ, all is utterly worthless. It is through the heart that the Holy Ghost instructs us. Hence, the apostle prayed for the saints at Ephesus, that "the eyes of their _heart_ [καρδίας, not διανοίας] might be enlightened;" and again, "That Christ may dwell in your _heart_ by faith."