I definitely agree with this statement. Of course, we should always make an effort to get rid of idle thoughts during prayer. Thus, bearing in mind death, the Judgement and hell will help us to realise all the dreadfulness of our sins and to repent as one of the key purposes of prayer is repentance. At the same time, thoughts about heaven will definitely guard us from falling into despondency and give us hope.
Nevertheless, some spiritual fathers advice us to talk to God about everything that is vital for us, even about our earthly concerns and everyday problems.
Therefore, I agree with the Holy Fathers that when we read our morning and evening prayers, for example, we should concentrate on them but in the end we can appeal to the Lord personally and talk to Him with our own words discussing those matters that worry us.
