They shall mount up with wings as eagles is God's preliminary; the next promise is, they shall run, and not be weary; and they shall walk, and not faint. Hours of holy exultation are the reward for hours of patient plodding, waiting and working. Nature has its springs, and so has grace. Let us rejoice in the Lord always. Let us take Him to be our continual joy, whose heart is a fountain of blessedness and who is anointed with the oil of gladness above His fellows. We must not be disappointed if the tides are not always equally high. Even at low tide the ocean is just as full. Human nature could not stand perpetual excitement, even of a happy kind, and God often rests in His love. Let us live as unselfconsciously as possible, filling up each moment with faithful service and trusting Him to stir the springs at His will. Then as we go on in faithful service, we shall bear, again and again, His glad whisper: Well done, thou good and faithful servant: . . . enter thou into the joy of thy Lord (Matthew 25:21).