Firstly, there is a host of things associated with emotional spillage that we are not to do because they are incompatible with our heavenly identity. We are to put off anger, rage, malice, slander and filthy language (Col 3:8). We are to be angry but not sin, we are not to hold onto our anger, and we should get rid of all bitterness (Eph 4:26, 31). We are not to give way to fits of rage (Gal 5:20 NIV) or grumbling (Phil 2:14). These emotional outbursts may be so common in our homes, workplaces and churches that they might not seem a big deal. But as people being remade in the image of Christ, these outbursts are inappropriate (Eph 4:22-24). If we do these things, we are not being true to our new identity, nor are we loving those around us (Eph 5:1-2).
Furthermore, discontentment and distrust in God often underlie these everyday emotional outbursts. Think about the Israelites when they had just been delivered from Egypt (Exodus 16): sure, they were grateful that Pharaoh's army had drowned in the sea, but they were on foot in the desert, homeless, thirsty, hungry, unsure of the future, tired and stressed, and their children weren't sleeping and were behaving foully.2 If only they'd had beds, they could have got out of them on the right side. Instead, they found they were all as cheesed off as the next person; their emotions boiled over, and they let rip at Moses and Aaron.
Of course, their tantrum was not against their human leaders, but against God himself (Exod 16:8). They had quickly forgotten his miraculous power in delivering them from their oppressors, his sovereign provision at Marah and Elim, and the fulfilment of his gracious promises if they obeyed his commands (Exod 14; 15:22-27). Their grumbling was really discontentment and distrust in God. Often our emotional dark clouds, storms and flash floods spring from the same weather system.
Fortunately, our choice is not between living with a permanent ‘stiff upper lip’ and indiscriminately dumping our emotions on those around us. God made us emotional beings. Emotions can be a blessing, but just as there are some things that we are not to do in expressing them, there are things we should do that reflect our trust in God, our identity in Christ and our love for those around us.
The most obvious of these is the fruit of the Spirit (Gal 5:22-23). Since we live by the Spirit and not the law, we have been freed for lives that conform to and are shaped by the Spirit (Gal 5:13-18). Instead of our emotions destroying relationships (as they so often do), they are to build relationships in love. Even when we are miserable or discouraged, we can and should have joy and peace. Even if we are stressed and frustrated, we can and should show gentleness and self-control. Even if we are heavily hormonal, we can and should be patient and kind. No matter how we are feeling, we are to watch what we say and how we say it, for our words show the true state of our hearts and can do great harm (Luke 6:45; Prov 29:11; Jas 3:5-12; cf. Matt 15:11).
This imperative to build relationships and serve others in love applies even when our emotions are justified. Think about the Apostle Paul: he did not pretend he was anything but deeply distressed by the conduct of the Corinthians, and he told them so. But after his first painful visit to them, he chose not to grieve them further, and spared them the full impact of his anguish and tears by writing, rather than returning in person, so that they could amend their ways in his absence (2 Cor 1:15-2:4).
Compare Paul to King David on the death of his usurping son, Absalom, when his (understandable) grief got in the way of him doing what was right and meeting the demands of the moment (2 Samuel 18-19). David's unrestrained (and self-indulgent) grief had a devastating effect on those around him, and his emotional response not only prevented him from meeting God's demands on his life and serving the needs of his people, it also suggested that he had forgotten the sovereign hand of God in determining Absalom's fate. In short, his emotions did not reflect his trust in God.
What a contrast with Jesus Christ! He was despised and rejected, well-acquainted with sorrow and grief (Isa 53:3), and yet his emotional state did not prevent him from serving others and doing what he had been entrusted by God to do (e.g. John 11:32-45). Even in the garden of Gethsemane, in deep anguish with sweat falling like drops of blood, he did not make his friends suffer for their slumberous lack of commitment and understanding. He rebuked them, not to vent his spleen or bring them back down to earth with a thud, but to warn them and bring them into a greater understanding of what was really going on (Luke 22:39-46; Mark 14:32-41). His emotions displayed the reality and gravity of his situation, his tender care for his friends, and his complete trust in the sovereign love of God.
But what about those with affective disorders, like depression and anxiety? Surely they can be excused for making others around them suffer. They are sick, after all. Well, yes and no: even then, we have a God-given responsibility to suffer in a way that honours him and serves those around us.3 It will, no doubt, be difficult, and the demands of godliness might change depending on the severity of the illness, but provided it is not a psychotic illness, we still have to make choices about what we say and do, and how we say and do it. A medical diagnosis is not a licence for taking the brakes off our tongues and tempers, or for doubting the goodness and sovereignty of God. God's grace is always sufficient, and his power is made perfect in weakness (2 Cor 12:9).
Christ demands all of our lives—not just our minds, finances, marriages, careers, sexuality and so on. He demands that we turn away from all things contrary to his perfect righteousness. This includes what we do with our emotions—especially the ugly ones—even in those common refuges of unguarded emotions (e.g. in emails, blog posts, on the road or at home). At his return, the battle with our emotions will be over, and we will be where there is no more crying or pain, and nothing that is shameful or deceitful (Revelation 21-22). But in the meantime, be warned: there is no place in which we can sin emotionally, for there is no place in which we can hide from his Spirit (Psalm 139).
1 With apologies to Philippians 3:10.
2 Okay, I'm speculating here, but you get the picture.
3 Part of godly living in these situations is ensuring we get proper medical treatment, and that we humbly ask for the prayers and practical help of the saints.