The fact some can depart from the faith proves that a Christian can be lost and OSAS is not biblical.
Yes, God does His drawing through His word when men have been "taught", "heard" and "learned" that word, then men "cometh to Me (CHrist)".
God draws, men come.
Therefore God's drawing is not some mystical, irresistible drawing done apart from the word. Men come to Christ of their own volition upon being drawn by God through His word. And as long as one continues to "come to Christ" he will be raised up at the last day.
Funny how you miss Christ's words about the Father giving to Christ His people and they are the ones who will come to Him, in that they have not yet come, means they were drawn-compelled by God to Christ by an inward working power which was God at work within them, and they would not normally do so on their own... That is what true grace is, being saved is God's gift and is only for the elect whom God has foreknown BEFOREHAND as His people, whom He has chosen, not all men.
1 Peter 1New International Version (NIV)
1 Peter, an apostle of Jesus Christ,
To God’s elect,
exiles scattered throughout the provinces of Pontus, Galatia, Cappadocia, Asia and Bithynia,
2 who have been chosen
according to the foreknowledge of God the Father,
through the sanctifying work of the Spirit,
to be obedient to Jesus Christ
and sprinkled with his blood:
Grace and peace be yours in abundance.
The ELECT have been CHOSEN by FOREKNOWLEDGE of God, through the SANCTIFYING work of the Holy Spirit, to be OBEDIENT to Christ and SPRINKLED with His blood.
And only the ELECT have GRACE and PEACE with God.
Everyone of God's elect He has INDIVIDUALLY CALLED.
Romans 9
22 What if God, although choosing to show his wrath and make his power known, bore with great patience the objects of his wrath—prepared for destruction? 23 What if he did this to make the riches of his glory known to the objects of his mercy, whom he prepared in advance for glory— 24
even us, whom he also called, not only from the Jews but also from the Gentiles?