What is essential to contemplation and what is just sometimes, but not necessarily, associated with it? Louis Lallemant SJ explains:

The degrees of contemplation, according to some are, first, recollection of all the powers of the mind; secondly, semi-rapture; thirdly, complete rapture; fourthly, ecstasy  But this division expresses not so much the essence of contemplation as its accidents; for some times a soul without rapture will be favoured with a sublimer light, a clearer knowledge, a more excellent operation from God, than another who is favoured with the most extraordinary raptures and ecstasies  The Blessed Virgin was more elevated in contemplation than all the angels and saints united; and yet she had no raptures. Our Lord enjoyed the beatific vision without ecstasy. The blessed in heaven will have a perfectly free use of all their senses.

That tells us what contemplation doesn’t really consist in, just what we sometimes observe when watching contemplative souls. What, then, does contemplation consist in? Father Lallemant, in agreement with a John of the Cross or a Teresa of Jesus, says that contemplation in itself is

a perception of God or of divine things, simple, free, penetrating, certain, proceeding from love, and tending to love.

It’s a kind of suffering of divine things (passio divinorum) in the human person; and because God is supremely simple and loving, the “perception” or “view” of contemplation is increasingly simple and loving also. As a result, the effects of contemplation are important for this present life:

Without contemplation we will never advance far toward virtue… we will never break free of our weaknesses and our imperfections. We will always be attached to the earth, and will never raise ourselves much above the sentiments of nature. We will never be able to offer a perfect service to God. But with contemplation we will do more in a month, for ourselves and for others, than we would have been able to do without it in ten years. It produces… acts of sublime love for God such as one can hardly ever accomplish without this gift… and finally, it perfects faith and all the virtues.

No wonder that the saints counsel us to desire this gift earnestly and to genuinely prepare ourselves to receive it.