God draws the elect through His Word and Sacraments...

Furthermore, the declaration in John 6:44 is right and true, "No one can come to Me unless the Father who send Me draws him."  However, the Father will not do this without means, but has ordained His Word and Sacraments for this purpose as ordinary means and instruments.  It is not the will of the Father or of the Son that a person should not hear or should despite the preaching of His Word and with for the drawing of the Father without the Word and sacraments.  For the Father draws indeed by the power of His Holy Spirit.  However, He works according to His usual way.  He works by the hearing of His holy, divine Word, as with a net, by which the elect are plucked from the devil's jaws.  Every poor sinner should therefore attend to the Word, hear it attentively, and not doubt the Father's drawing.  For the Holy Spirit will be with His world in His power, and will work by it.  That is the Father's drawing.
~FSD, XI, 76-77

Election is founded upon Christ's merit and God's gracious will...

The Holy Spirit dwells in the elect, who have become believers, as in His temple.  He is not idle in them, but moves God's children to obey God's commands.  Therefore, believers, too, should not be idle, much less resist the work of God's Spirit.  They should practice all Christian virtues, in all godliness, modesty, temperance, patience, and brotherly love; and they should give all diligence to make their calling and election sure.  They should do this so that the more they find the Spirit's power and strength within them, they may doubt their election less. For the Spirit bears witness to the elect that they are God's children.  Sometimes they fall into temptation so terribly that they imagine they can no longer perceive the power of God's indwelling Spirit, and so they say with David, "I had said in my alarm, 'I am cut off from Your sight'" (Psalm 31:22).  Yet they should, without regard to what they experience in themselves, again say with David the words immediately following (as is written in the same place), "But You heard the voice of my pleas for mercy when I cried to You for help."

Our election to eternal life is founded not on our godliness or virtue, but on Christ's merit alone and His Father's gracious will.  He cannot deny Himself, because His is unchangeable in will and essence.  Therefore, when His children depart from obedience and stubble, He has called them to repentance again through the Word, and the Holy Spirit wants by the Word to be effective in them for conversion.  When they turn to Him again in true repentance by a right faith, He will always show His old paternal heart to all who tremble at His Word and from their heart turn again to Him, as it is written:

If a man divorces his wife and she goes from him and becomes another man's wife, will he return to her?  Would not that land be greatly polluted?  You have played the whore with many lovers; [yet returned again to Me,] declares the Lord. (Jeremiah 3:1).
~BOC, FSD, XI 73-75