“’The pure of heart will see God,’ according to the Lord’s infallible word (Mt. 5:8), according to his capacity, receiving as much as his mind can sustain; yet the infinite and incomprehensible nature of the Godhead remains beyond all understanding. For ‘the magnificence of His glory,’ as the Prophet says (Ps. 144-5), has no end, and as we contemplate Him He remains ever the same, at the same distance above us. The Great David enjoyed in his heart those glorious elevations as he progressed from strength to strength; and yet he cried to God: Lord, ‘Thou art the most High,’ forever and ever (Ps. 82:19). And by this I think he means that in all the infinite eternity of centuries, the man who runs towards Thee constantly becomes greater as he rises higher, ever growing in proportion to his increase in grace. ‘Thou,’ indeed, ‘art the most High,’ abiding forever, and canst never seem smaller to those who approach Thee, for Thou art always to the same degree higher and loftier than th! e faculties of those who are rising. St. Gregory of Nyssa”
and
“As a blacksmith can do nothing without the help of fire, however skilled he may be in wielding his tools, so a man should do everything he can on his side to purify his heart, using virtues as tools for this purpose; but without fire of the Spirit, everything he does will remain inactive and useless for his aim, for by itself what he does is powerless to cleanse the soul of its dirt and foulness.” St. Simeon the New Theologian
It’s not even a matter of us cooperating with God.
HE works in us to will and to do according to HIS good pleasure.
The very motivation to seek Him comes from Him Himself. We can’t even do that without His enabling.
This business of us doing it and needing the *help* of God to make it worthwhile makes it us doing it in out own strength and God is added as necessary.